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On February 23, 2018, PubMed Central Canada (PMC Canada) will be taken offline permanently. No author manuscripts will be deleted, and the approximately 2,900 manuscripts authored by Canadian Institutes of Health Research (CIHR)-funded researchers currently in the archive will be copied to the National Research Council’s (NRC) Digital Repository over the coming months. These manuscripts along with all other content will also remain publicly searchable on PubMed Central (US) and Europe PubMed Central, meaning such manuscripts will continue to be compliant with the Tri-Agency Open Access Policy on Publications.

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1.  Clearance of senescent decidual cells by uterine natural killer cells in cycling human endometrium 
eLife  null;6:e31274.
In cycling human endometrium, menstruation is followed by rapid estrogen-dependent growth. Upon ovulation, progesterone and rising cellular cAMP levels activate the transcription factor Forkhead box O1 (FOXO1) in endometrial stromal cells (EnSCs), leading to cell cycle exit and differentiation into decidual cells that control embryo implantation. Here we show that FOXO1 also causes acute senescence of a subpopulation of decidualizing EnSCs in an IL-8 dependent manner. Selective depletion or enrichment of this subpopulation revealed that decidual senescence drives the transient inflammatory response associated with endometrial receptivity. Further, senescent cells prevent differentiation of endometrial mesenchymal stem cells in decidualizing cultures. As the cycle progresses, IL-15 activated uterine natural killer (uNK) cells selectively target and clear senescent decidual cells through granule exocytosis. Our findings reveal that acute decidual senescence governs endometrial rejuvenation and remodeling at embryo implantation, and suggest a critical role for uNK cells in maintaining homeostasis in cycling endometrium.
doi:10.7554/eLife.31274
PMCID: PMC5724991  PMID: 29227245
Endometrium; Senescence; uterine natural killer cells; Immunosurveillance; Implantation; receptivity; Human
2.  Integration of kinase and calcium signaling at the level of chromatin underlies inducible gene activation in T cells 
TCR signaling pathways cooperate to activate the inducible transcription factors NF-κB, NFAT and AP-1. Here, using the calcium ionophore ionomycin and/or PMA on Jurkat T cells, we show that the gene expression program associated with activation of TCR signaling is closely related to specific chromatin landscapes. We find that calcium and kinase signaling cooperate to induce chromatin remodeling at ~2100 chromatin regions, which demonstrate enriched binding motifs for inducible factors and correlate with target gene expression. We found that these regions typically function as inducible enhancers. Many of these elements contain composite NFAT/AP-1 sites, which typically support cooperative binding, thus further reinforcing the need for cooperation between calcium and kinase signaling in the activation of genes in T cells. In contrast, treatment with PMA or ionomycin alone induces chromatin remodeling at far fewer regions (~600 and ~350, respectively), which mostly represent a subset of those induced by co-stimulation. This suggests that the integration of T cell receptor signaling largely occurs at the level of chromatin, which we propose plays a crucial role in regulating T cell activation.
doi:10.4049/jimmunol.1602033
PMCID: PMC5632840  PMID: 28904128
3.  Loss of Endometrial Sodium Glucose Cotransporter SGLT1 is Detrimental to Embryo Survival and Fetal Growth in Pregnancy 
Scientific Reports  2017;7:12612.
Embryo implantation requires a hospitable uterine environment. A key metabolic change that occurs during the peri-implantation period, and throughout early pregnancy, is the rise in endometrial glycogen content. Glycogen accumulation requires prior cellular uptake of glucose. Here we show that both human and murine endometrial epithelial cells express the high affinity Na+-coupled glucose carrier SGLT1. Ussing chamber experiments revealed electrogenic glucose transport across the endometrium in wild type (Slc5a1 +/+) but not in SGLT1 deficient (Slc5a1 −/−) mice. Endometrial glycogen content, litter size and weight of offspring at birth were significantly lower in Slc5a1 −/− mice. In humans, SLC5A1 expression was upregulated upon decidualization of primary endometrial stromal cells. Endometrial SLC5A1 expression during the implantation window was attenuated in patients with recurrent pregnancy loss when compared with control subjects. Our findings reveal a novel mechanism establishing adequate endometrial glycogen stores for pregnancy. Disruption of this histiotrophic pathway leads to adverse pregnancy outcome.
doi:10.1038/s41598-017-11674-3
PMCID: PMC5626729  PMID: 28974690
4.  Integration of Kinase and Calcium Signaling at the Level of Chromatin Underlies Inducible Gene Activation in T Cells 
TCR signaling pathways cooperate to activate the inducible transcription factors NF-κB, NFAT, and AP-1. In this study, using the calcium ionophore ionomycin and/or PMA on Jurkat T cells, we show that the gene expression program associated with activation of TCR signaling is closely related to specific chromatin landscapes. We find that calcium and kinase signaling cooperate to induce chromatin remodeling at ∼2100 chromatin regions, which demonstrate enriched binding motifs for inducible factors and correlate with target gene expression. We found that these regions typically function as inducible enhancers. Many of these elements contain composite NFAT/AP-1 sites, which typically support cooperative binding, thus further reinforcing the need for cooperation between calcium and kinase signaling in the activation of genes in T cells. In contrast, treatment with PMA or ionomycin alone induces chromatin remodeling at far fewer regions (∼600 and ∼350, respectively), which mostly represent a subset of those induced by costimulation. This suggests that the integration of TCR signaling largely occurs at the level of chromatin, which we propose plays a crucial role in regulating T cell activation.
doi:10.4049/jimmunol.1602033
PMCID: PMC5632840  PMID: 28904128
5.  Inducible chromatin priming is associated with the establishment of immunological memory in T cells 
The EMBO Journal  2016;35(5):515-535.
Abstract
Immunological memory is a defining feature of vertebrate physiology, allowing rapid responses to repeat infections. However, the molecular mechanisms required for its establishment and maintenance remain poorly understood. Here, we demonstrated that the first steps in the acquisition of T‐cell memory occurred during the initial activation phase of naïve T cells by an antigenic stimulus. This event initiated extensive chromatin remodeling that reprogrammed immune response genes toward a stably maintained primed state, prior to terminal differentiation. Activation induced the transcription factors NFAT and AP‐1 which created thousands of new DNase I‐hypersensitive sites (DHSs), enabling ETS‐1 and RUNX1 recruitment to previously inaccessible sites. Significantly, these DHSs remained stable long after activation ceased, were preserved following replication, and were maintained in memory‐phenotype cells. We show that primed DHSs maintain regions of active chromatin in the vicinity of inducible genes and enhancers that regulate immune responses. We suggest that this priming mechanism may contribute to immunological memory in T cells by facilitating the induction of nearby inducible regulatory elements in previously activated T cells.
doi:10.15252/embj.201592534
PMCID: PMC4772849  PMID: 26796577
chromatin; epigenetics; gene regulation; immunity; memory T cell; Chromatin, Epigenetics, Genomics & Functional Genomics; Immunology
6.  31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016): part one 
Lundqvist, Andreas | van Hoef, Vincent | Zhang, Xiaonan | Wennerberg, Erik | Lorent, Julie | Witt, Kristina | Sanz, Laia Masvidal | Liang, Shuo | Murray, Shannon | Larsson, Ola | Kiessling, Rolf | Mao, Yumeng | Sidhom, John-William | Bessell, Catherine A. | Havel, Jonathan | Schneck, Jonathan | Chan, Timothy A. | Sachsenmeier, Eliot | Woods, David | Berglund, Anders | Ramakrishnan, Rupal | Sodre, Andressa | Weber, Jeffrey | Zappasodi, Roberta | Li, Yanyun | Qi, Jingjing | Wong, Philip | Sirard, Cynthia | Postow, Michael | Newman, Walter | Koon, Henry | Velcheti, Vamsidhar | Callahan, Margaret K. | Wolchok, Jedd D. | Merghoub, Taha | Lum, Lawrence G. | Choi, Minsig | Thakur, Archana | Deol, Abhinav | Dyson, Gregory | Shields, Anthony | Haymaker, Cara | Uemura, Marc | Murthy, Ravi | James, Marihella | Wang, Daqing | Brevard, Julie | Monaghan, Catherine | Swann, Suzanne | Geib, James | Cornfeld, Mark | Chunduru, Srinivas | Agrawal, Sudhir | Yee, Cassian | Wargo, Jennifer | Patel, Sapna P. | Amaria, Rodabe | Tawbi, Hussein | Glitza, Isabella | Woodman, Scott | Hwu, Wen-Jen | Davies, Michael A. | Hwu, Patrick | Overwijk, Willem W. | Bernatchez, Chantale | Diab, Adi | Massarelli, Erminia | Segal, Neil H. | Ribrag, Vincent | Melero, Ignacio | Gangadhar, Tara C. | Urba, Walter | Schadendorf, Dirk | Ferris, Robert L. | Houot, Roch | Morschhauser, Franck | Logan, Theodore | Luke, Jason J. | Sharfman, William | Barlesi, Fabrice | Ott, Patrick A. | Mansi, Laura | Kummar, Shivaani | Salles, Gilles | Carpio, Cecilia | Meier, Roland | Krishnan, Suba | McDonald, Dan | Maurer, Matthew | Gu, Xuemin | Neely, Jaclyn | Suryawanshi, Satyendra | Levy, Ronald | Khushalani, Nikhil | Wu, Jennifer | Zhang, Jinyu | Basher, Fahmin | Rubinstein, Mark | Bucsek, Mark | Qiao, Guanxi | MacDonald, Cameron | Hylander, Bonnie | Repasky, Elizabeth | Chatterjee, Shilpak | Daenthanasanmak, Anusara | Chakraborty, Paramita | Toth, Kyle | Meek, Megan | Garrett-Mayer, Elizabeth | Nishimura, Michael | Paulos, Chrystal | Beeson, Craig | Yu, Xuezhong | Mehrotra, Shikhar | Zhao, Fei | Evans, Kathy | Xiao, Christine | Holtzhausen, Alisha | Hanks, Brent A. | Scharping, Nicole | Menk, Ashley V. | Moreci, Rebecca | Whetstone, Ryan | Dadey, Rebekah | Watkins, Simon | Ferris, Robert | Delgoffe, Greg M. | Peled, Jonathan | Devlin, Sean | Staffas, Anna | Lumish, Melissa | Rodriguez, Kori Porosnicu | Ahr, Katya | Perales, Miguel | Giralt, Sergio | Taur, Ying | Pamer, Eric | van den Brink, Marcel R. M. | Jenq, Robert | Annels, Nicola | Pandha, Hardev | Simpson, Guy | Mostafid, Hugh | Harrington, Kevin | Melcher, Alan | Grose, Mark | Davies, Bronwyn | Au, Gough | Karpathy, Roberta | Shafren, Darren | Ricca, Jacob | Merghoub, Taha | Wolchok, Jedd D. | Zamarin, Dmitriy | Batista, Luciana | Marliot, Florence | Vasaturo, Angela | Carpentier, Sabrina | Poggionovo, Cécile | Frayssinet, Véronique | Fieschi, Jacques | Van den Eynde, Marc | Pagès, Franck | Galon, Jérôme | Hermitte, Fabienne | Smith, Sean G. | Nguyen, Khue | Ravindranathan, Sruthi | Koppolu, Bhanu | Zaharoff, David | Schvartsman, Gustavo | Bassett, Roland | McQuade, Jennifer L. | Haydu, Lauren E. | Davies, Michael A. | Tawbi, Hussein | Glitza, Isabella | Kline, Douglas | Chen, Xiufen | Fosco, Dominick | Kline, Justin | Overacre, Abigail | Chikina, Maria | Brunazzi, Erin | Shayan, Gulidanna | Horne, William | Kolls, Jay | Ferris, Robert L. | Delgoffe, Greg M. | Bruno, Tullia C. | Workman, Creg | Vignali, Dario | Adusumilli, Prasad S. | Ansa-Addo, Ephraim A | Li, Zihai | Gerry, Andrew | Sanderson, Joseph P. | Howe, Karen | Docta, Roslin | Gao, Qian | Bagg, Eleanor A. L. | Tribble, Nicholas | Maroto, Miguel | Betts, Gareth | Bath, Natalie | Melchiori, Luca | Lowther, Daniel E. | Ramachandran, Indu | Kari, Gabor | Basu, Samik | Binder-Scholl, Gwendolyn | Chagin, Karen | Pandite, Lini | Holdich, Tom | Amado, Rafael | Zhang, Hua | Glod, John | Bernstein, Donna | Jakobsen, Bent | Mackall, Crystal | Wong, Ryan | Silk, Jonathan D. | Adams, Katherine | Hamilton, Garth | Bennett, Alan D. | Brett, Sara | Jing, Junping | Quattrini, Adriano | Saini, Manoj | Wiedermann, Guy | Gerry, Andrew | Jakobsen, Bent | Binder-Scholl, Gwendolyn | Brewer, Joanna | Duong, MyLinh | Lu, An | Chang, Peter | Mahendravada, Aruna | Shinners, Nicholas | Slawin, Kevin | Spencer, David M. | Foster, Aaron E. | Bayle, J. Henri | Bergamaschi, Cristina | Ng, Sinnie Sin Man | Nagy, Bethany | Jensen, Shawn | Hu, Xintao | Alicea, Candido | Fox, Bernard | Felber, Barbara | Pavlakis, George | Chacon, Jessica | Yamamoto, Tori | Garrabrant, Thomas | Cortina, Luis | Powell, Daniel J. | Donia, Marco | Kjeldsen, Julie Westerlin | Andersen, Rikke | Westergaard, Marie Christine Wulff | Bianchi, Valentina | Legut, Mateusz | Attaf, Meriem | Dolton, Garry | Szomolay, Barbara | Ott, Sascha | Lyngaa, Rikke | Hadrup, Sine Reker | Sewell, Andrew Kelvin | Svane, Inge Marie | Fan, Aaron | Kumai, Takumi | Celis, Esteban | Frank, Ian | Stramer, Amanda | Blaskovich, Michelle A. | Wardell, Seth | Fardis, Maria | Bender, James | Lotze, Michael T. | Goff, Stephanie L. | Zacharakis, Nikolaos | Assadipour, Yasmine | Prickett, Todd D. | Gartner, Jared J. | Somerville, Robert | Black, Mary | Xu, Hui | Chinnasamy, Harshini | Kriley, Isaac | Lu, Lily | Wunderlich, John | Robbins, Paul F. | Rosenberg, Steven | Feldman, Steven A. | Trebska-McGowan, Kasia | Kriley, Isaac | Malekzadeh, Parisa | Payabyab, Eden | Sherry, Richard | Rosenberg, Steven | Goff, Stephanie L. | Gokuldass, Aishwarya | Blaskovich, Michelle A. | Kopits, Charlene | Rabinovich, Brian | Lotze, Michael T. | Green, Daniel S. | Kamenyeva, Olena | Zoon, Kathryn C. | Annunziata, Christina M. | Hammill, Joanne | Helsen, Christopher | Aarts, Craig | Bramson, Jonathan | Harada, Yui | Yonemitsu, Yoshikazu | Helsen, Christopher | Hammill, Joanne | Mwawasi, Kenneth | Denisova, Galina | Bramson, Jonathan | Giri, Rajanish | Jin, Benjamin | Campbell, Tracy | Draper, Lindsey M. | Stevanovic, Sanja | Yu, Zhiya | Weissbrich, Bianca | Restifo, Nicholas P. | Trimble, Cornelia L. | Rosenberg, Steven | Hinrichs, Christian S. | Tsang, Kwong | Fantini, Massimo | Hodge, James W. | Fujii, Rika | Fernando, Ingrid | Jochems, Caroline | Heery, Christopher | Gulley, James | Soon-Shiong, Patrick | Schlom, Jeffrey | Jing, Weiqing | Gershan, Jill | Blitzer, Grace | Weber, James | McOlash, Laura | Johnson, Bryon D. | Kiany, Simin | Gangxiong, Huang | Kleinerman, Eugenie S. | Klichinsky, Michael | Ruella, Marco | Shestova, Olga | Kenderian, Saad | Kim, Miriam | Scholler, John | June, Carl H. | Gill, Saar | Moogk, Duane | Zhong, Shi | Yu, Zhiya | Liadi, Ivan | Rittase, William | Fang, Victoria | Dougherty, Janna | Perez-Garcia, Arianne | Osman, Iman | Zhu, Cheng | Varadarajan, Navin | Restifo, Nicholas P. | Frey, Alan | Krogsgaard, Michelle | Landi, Daniel | Fousek, Kristen | Mukherjee, Malini | Shree, Ankita | Joseph, Sujith | Bielamowicz, Kevin | Byrd, Tiara | Ahmed, Nabil | Hegde, Meenakshi | Lee, Sylvia | Byrd, David | Thompson, John | Bhatia, Shailender | Tykodi, Scott | Delismon, Judy | Chu, Liz | Abdul-Alim, Siddiq | Ohanian, Arpy | DeVito, Anna Marie | Riddell, Stanley | Margolin, Kim | Magalhaes, Isabelle | Mattsson, Jonas | Uhlin, Michael | Nemoto, Satoshi | Villarroel, Patricio Pérez | Nakagawa, Ryosuke | Mule, James J. | Mailloux, Adam W. | Mata, Melinda | Nguyen, Phuong | Gerken, Claudia | DeRenzo, Christopher | Spencer, David M. | Gottschalk, Stephen | Mathieu, Mélissa | Pelletier, Sandy | Stagg, John | Turcotte, Simon | Minutolo, Nicholas | Sharma, Prannda | Tsourkas, Andrew | Powell, Daniel J. | Mockel-Tenbrinck, Nadine | Mauer, Daniela | Drechsel, Katharina | Barth, Carola | Freese, Katharina | Kolrep, Ulrike | Schult, Silke | Assenmacher, Mario | Kaiser, Andrew | Mullinax, John | Hall, MacLean | Le, Julie | Kodumudi, Krithika | Royster, Erica | Richards, Allison | Gonzalez, Ricardo | Sarnaik, Amod | Pilon-Thomas, Shari | Nielsen, Morten | Krarup-Hansen, Anders | Hovgaard, Dorrit | Petersen, Michael Mørk | Loya, Anand Chainsukh | Junker, Niels | Svane, Inge Marie | Rivas, Charlotte | Parihar, Robin | Gottschalk, Stephen | Rooney, Cliona M. | Qin, Haiying | Nguyen, Sang | Su, Paul | Burk, Chad | Duncan, Brynn | Kim, Bong-Hyun | Kohler, M. Eric | Fry, Terry | Rao, Arjun A. | Teyssier, Noam | Pfeil, Jacob | Sgourakis, Nikolaos | Salama, Sofie | Haussler, David | Richman, Sarah A. | Nunez-Cruz, Selene | Gershenson, Zack | Mourelatos, Zissimos | Barrett, David | Grupp, Stephan | Milone, Michael | Rodriguez-Garcia, Alba | Robinson, Matthew K. | Adams, Gregory P. | Powell, Daniel J. | Santos, João | Havunen, Riikka | Siurala, Mikko | Cervera-Carrascón, Víctor | Parviainen, Suvi | Antilla, Marjukka | Hemminki, Akseli | Sethuraman, Jyothi | Santiago, Laurelis | Chen, Jie Qing | Dai, Zhimin | Wardell, Seth | Bender, James | Lotze, Michael T. | Sha, Huizi | Su, Shu | Ding, Naiqing | Liu, Baorui | Stevanovic, Sanja | Pasetto, Anna | Helman, Sarah R. | Gartner, Jared J. | Prickett, Todd D. | Robbins, Paul F. | Rosenberg, Steven A. | Hinrichs, Christian S. | Bhatia, Shailender | Burgess, Melissa | Zhang, Hui | Lee, Tien | Klingemann, Hans | Soon-Shiong, Patrick | Nghiem, Paul | Kirkwood, John M. | Rossi, John M. | Sherman, Marika | Xue, Allen | Shen, Yueh-wei | Navale, Lynn | Rosenberg, Steven A. | Kochenderfer, James N. | Bot, Adrian | Veerapathran, Anandaraman | Gokuldass, Aishwarya | Stramer, Amanda | Sethuraman, Jyothi | Blaskovich, Michelle A. | Wiener, Doris | Frank, Ian | Santiago, Laurelis | Rabinovich, Brian | Fardis, Maria | Bender, James | Lotze, Michael T. | Waller, Edmund K. | Li, Jian-Ming | Petersen, Christopher | Blazar, Bruce R. | Li, Jingxia | Giver, Cynthia R. | Wang, Ziming | Grossenbacher, Steven K. | Sturgill, Ian | Canter, Robert J. | Murphy, William J. | Zhang, Congcong | Burger, Michael C. | Jennewein, Lukas | Waldmann, Anja | Mittelbronn, Michel | Tonn, Torsten | Steinbach, Joachim P. | Wels, Winfried S. | Williams, Jason B. | Zha, Yuanyuan | Gajewski, Thomas F. | Williams, LaTerrica C. | Krenciute, Giedre | Kalra, Mamta | Louis, Chrystal | Gottschalk, Stephen | Xin, Gang | Schauder, David | Jiang, Aimin | Joshi, Nikhil | Cui, Weiguo | Zeng, Xue | Menk, Ashley V. | Scharping, Nicole | Delgoffe, Greg M. | Zhao, Zeguo | Hamieh, Mohamad | Eyquem, Justin | Gunset, Gertrude | Bander, Neil | Sadelain, Michel | Askmyr, David | Abolhalaj, Milad | Lundberg, Kristina | Greiff, Lennart | Lindstedt, Malin | Angell, Helen K. | Kim, Kyoung-Mee | Kim, Seung-Tae | Kim, Sung | Sharpe, Alan D. | Ogden, Julia | Davenport, Anna | Hodgson, Darren R. | Barrett, Carl | Lee, Jeeyun | Kilgour, Elaine | Hanson, Jodi | Caspell, Richard | Karulin, Alexey | Lehmann, Paul | Ansari, Tameem | Schiller, Annemarie | Sundararaman, Srividya | Lehmann, Paul | Hanson, Jodi | Roen, Diana | Karulin, Alexey | Lehmann, Paul | Ayers, Mark | Levitan, Diane | Arreaza, Gladys | Liu, Fang | Mogg, Robin | Bang, Yung-Jue | O’Neil, Bert | Cristescu, Razvan | Friedlander, Philip | Wassman, Karl | Kyi, Chrisann | Oh, William | Bhardwaj, Nina | Bornschlegl, Svetlana | Gustafson, Michael P. | Gastineau, Dennis A. | Parney, Ian F. | Dietz, Allan B. | Carvajal-Hausdorf, Daniel | Mani, Nikita | Velcheti, Vamsidhar | Schalper, Kurt | Rimm, David | Chang, Serena | Levy, Ronald | Kurland, John | Krishnan, Suba | Ahlers, Christoph Matthias | Jure-Kunkel, Maria | Cohen, Lewis | Maecker, Holden | Kohrt, Holbrook | Chen, Shuming | Crabill, George | Pritchard, Theresa | McMiller, Tracee | Pardoll, Drew | Pan, Fan | Topalian, Suzanne | Danaher, Patrick | Warren, Sarah | Dennis, Lucas | White, Andrew M. | D’Amico, Leonard | Geller, Melissa | Disis, Mary L. | Beechem, Joseph | Odunsi, Kunle | Fling, Steven | Derakhshandeh, Roshanak | Webb, Tonya J. | Dubois, Sigrid | Conlon, Kevin | Bryant, Bonita | Hsu, Jennifer | Beltran, Nancy | Müller, Jürgen | Waldmann, Thomas | Duhen, Rebekka | Duhen, Thomas | Thompson, Lucas | Montler, Ryan | Weinberg, Andrew | Kates, Max | Early, Brandon | Yusko, Erik | Schreiber, Taylor H. | Bivalacqua, Trinity J. | Ayers, Mark | Lunceford, Jared | Nebozhyn, Michael | Murphy, Erin | Loboda, Andrey | Kaufman, David R. | Albright, Andrew | Cheng, Jonathan | Kang, S. Peter | Shankaran, Veena | Piha-Paul, Sarina A. | Yearley, Jennifer | Seiwert, Tanguy | Ribas, Antoni | McClanahan, Terrill K. | Cristescu, Razvan | Mogg, Robin | Ayers, Mark | Albright, Andrew | Murphy, Erin | Yearley, Jennifer | Sher, Xinwei | Liu, Xiao Qiao | Nebozhyn, Michael | Lunceford, Jared | Joe, Andrew | Cheng, Jonathan | Plimack, Elizabeth | Ott, Patrick A. | McClanahan, Terrill K. | Loboda, Andrey | Kaufman, David R. | Forrest-Hay, Alex | Guyre, Cheryl A. | Narumiya, Kohei | Delcommenne, Marc | Hirsch, Heather A. | Deshpande, Amit | Reeves, Jason | Shu, Jenny | Zi, Tong | Michaelson, Jennifer | Law, Debbie | Trehu, Elizabeth | Sathyanaryanan, Sriram | Hodkinson, Brendan P. | Hutnick, Natalie A. | Schaffer, Michael E. | Gormley, Michael | Hulett, Tyler | Jensen, Shawn | Ballesteros-Merino, Carmen | Dubay, Christopher | Afentoulis, Michael | Reddy, Ashok | David, Larry | Fox, Bernard | Jayant, Kumar | Agrawal, Swati | Agrawal, Rajendra | Jeyakumar, Ghayathri | Kim, Seongho | Kim, Heejin | Silski, Cynthia | Suisham, Stacey | Heath, Elisabeth | Vaishampayan, Ulka | Vandeven, Natalie | Viller, Natasja Nielsen | O’Connor, Alison | Chen, Hui | Bossen, Bolette | Sievers, Eric | Uger, Robert | Nghiem, Paul | Johnson, Lisa | Kao, Hsiang-Fong | Hsiao, Chin-Fu | Lai, Shu-Chuan | Wang, Chun-Wei | Ko, Jenq-Yuh | Lou, Pei-Jen | Lee, Tsai-Jan | Liu, Tsang-Wu | Hong, Ruey-Long | Kearney, Staci J. | Black, Joshua C. | Landis, Benjamin J. | Koegler, Sally | Hirsch, Brooke | Gianani, Roberto | Kim, Jeffrey | He, Ming-Xiao | Zhang, Bingqing | Su, Nan | Luo, Yuling | Ma, Xiao-Jun | Park, Emily | Kim, Dae Won | Copploa, Domenico | Kothari, Nishi | doo Chang, Young | Kim, Richard | Kim, Namyong | Lye, Melvin | Wan, Ee | Kim, Namyong | Lye, Melvin | Wan, Ee | Kim, Namyong | Lye, Melvin | Wan, Ee | Knaus, Hanna A. | Berglund, Sofia | Hackl, Hubert | Karp, Judith E. | Gojo, Ivana | Luznik, Leo | Hong, Henoch S. | Koch, Sven D. | Scheel, Birgit | Gnad-Vogt, Ulrike | Kallen, Karl-Josef | Wiegand, Volker | Backert, Linus | Kohlbacher, Oliver | Hoerr, Ingmar | Fotin-Mleczek, Mariola | Billingsley, James M. | Koguchi, Yoshinobu | Conrad, Valerie | Miller, William | Gonzalez, Iliana | Poplonski, Tomasz | Meeuwsen, Tanisha | Howells-Ferreira, Ana | Rattray, Rogan | Campbell, Mary | Bifulco, Carlo | Dubay, Christopher | Bahjat, Keith | Curti, Brendan | Urba, Walter | Vetsika, E-K | Kallergi, G. | Aggouraki, Despoina | Lyristi, Z. | Katsarlinos, P. | Koinis, Filippos | Georgoulias, V. | Kotsakis, Athanasios | Martin, Nathan T. | Aeffner, Famke | Kearney, Staci J. | Black, Joshua C. | Cerkovnik, Logan | Pratte, Luke | Kim, Rebecca | Hirsch, Brooke | Krueger, Joseph | Gianani, Roberto | Martínez-Usatorre, Amaia | Jandus, Camilla | Donda, Alena | Carretero-Iglesia, Laura | Speiser, Daniel E. | Zehn, Dietmar | Rufer, Nathalie | Romero, Pedro | Panda, Anshuman | Mehnert, Janice | Hirshfield, Kim M. | Riedlinger, Greg | Damare, Sherri | Saunders, Tracie | Sokol, Levi | Stein, Mark | Poplin, Elizabeth | Rodriguez-Rodriguez, Lorna | Silk, Ann | Chan, Nancy | Frankel, Melissa | Kane, Michael | Malhotra, Jyoti | Aisner, Joseph | Kaufman, Howard L. | Ali, Siraj | Ross, Jeffrey | White, Eileen | Bhanot, Gyan | Ganesan, Shridar | Monette, Anne | Bergeron, Derek | Amor, Amira Ben | Meunier, Liliane | Caron, Christine | Morou, Antigoni | Kaufmann, Daniel | Liberman, Moishe | Jurisica, Igor | Mes-Masson, Anne-Marie | Hamzaoui, Kamel | Lapointe, Rejean | Mongan, Ann | Ku, Yuan-Chieh | Tom, Warren | Sun, Yongming | Pankov, Alex | Looney, Tim | Au-Young, Janice | Hyland, Fiona | Conroy, Jeff | Morrison, Carl | Glenn, Sean | Burgher, Blake | Ji, He | Gardner, Mark | Mongan, Ann | Omilian, Angela R. | Conroy, Jeff | Bshara, Wiam | Angela, Omilian | Burgher, Blake | Ji, He | Glenn, Sean | Morrison, Carl | Mongan, Ann | Obeid, Joseph M. | Erdag, Gulsun | Smolkin, Mark E. | Deacon, Donna H. | Patterson, James W. | Chen, Lieping | Bullock, Timothy N. | Slingluff, Craig L. | Obeid, Joseph M. | Erdag, Gulsun | Deacon, Donna H. | Slingluff, Craig L. | Bullock, Timothy N. | Loffredo, John T. | Vuyyuru, Raja | Beyer, Sophie | Spires, Vanessa M. | Fox, Maxine | Ehrmann, Jon M. | Taylor, Katrina A. | Korman, Alan J. | Graziano, Robert F. | Page, David | Sanchez, Katherine | Ballesteros-Merino, Carmen | Martel, Maritza | Bifulco, Carlo | Urba, Walter | Fox, Bernard | Patel, Sapna P. | De Macedo, Mariana Petaccia | Qin, Yong | Reuben, Alex | Spencer, Christine | Guindani, Michele | Bassett, Roland | Wargo, Jennifer | Racolta, Adriana | Kelly, Brian | Jones, Tobin | Polaske, Nathan | Theiss, Noah | Robida, Mark | Meridew, Jeffrey | Habensus, Iva | Zhang, Liping | Pestic-Dragovich, Lidija | Tang, Lei | Sullivan, Ryan J. | Logan, Theodore | Khushalani, Nikhil | Margolin, Kim | Koon, Henry | Olencki, Thomas | Hutson, Thomas | Curti, Brendan | Roder, Joanna | Blackmon, Shauna | Roder, Heinrich | Stewart, John | Amin, Asim | Ernstoff, Marc S. | Clark, Joseph I. | Atkins, Michael B. | Kaufman, Howard L. | Sosman, Jeffrey | Weber, Jeffrey | McDermott, David F. | Weber, Jeffrey | Kluger, Harriet | Halaban, Ruth | Snzol, Mario | Roder, Heinrich | Roder, Joanna | Asmellash, Senait | Steingrimsson, Arni | Blackmon, Shauna | Sullivan, Ryan J. | Wang, Chichung | Roman, Kristin | Clement, Amanda | Downing, Sean | Hoyt, Clifford | Harder, Nathalie | Schmidt, Guenter | Schoenmeyer, Ralf | Brieu, Nicolas | Yigitsoy, Mehmet | Madonna, Gabriele | Botti, Gerardo | Grimaldi, Antonio | Ascierto, Paolo A. | Huss, Ralf | Athelogou, Maria | Hessel, Harald | Harder, Nathalie | Buchner, Alexander | Schmidt, Guenter | Stief, Christian | Huss, Ralf | Binnig, Gerd | Kirchner, Thomas | Sellappan, Shankar | Thyparambil, Sheeno | Schwartz, Sarit | Cecchi, Fabiola | Nguyen, Andrew | Vaske, Charles | Hembrough, Todd
Journal for Immunotherapy of Cancer  2016;4(Suppl 1):1-106.
doi:10.1186/s40425-016-0172-7
PMCID: PMC5123387
7.  Inducible chromatin priming is associated with the establishment of immunological memory in T cells 
The EMBO Journal  2016;35(5):515-535.
Abstract
Immunological memory is a defining feature of vertebrate physiology, allowing rapid responses to repeat infections. However, the molecular mechanisms required for its establishment and maintenance remain poorly understood. Here, we demonstrated that the first steps in the acquisition of T‐cell memory occurred during the initial activation phase of naïve T cells by an antigenic stimulus. This event initiated extensive chromatin remodeling that reprogrammed immune response genes toward a stably maintained primed state, prior to terminal differentiation. Activation induced the transcription factors NFAT and AP‐1 which created thousands of new DNase I‐hypersensitive sites (DHSs), enabling ETS‐1 and RUNX1 recruitment to previously inaccessible sites. Significantly, these DHSs remained stable long after activation ceased, were preserved following replication, and were maintained in memory‐phenotype cells. We show that primed DHSs maintain regions of active chromatin in the vicinity of inducible genes and enhancers that regulate immune responses. We suggest that this priming mechanism may contribute to immunological memory in T cells by facilitating the induction of nearby inducible regulatory elements in previously activated T cells.
doi:10.15252/embj.201592534
PMCID: PMC4772849  PMID: 26796577
chromatin; epigenetics; gene regulation; immunity; memory T cell; Chromatin, Epigenetics, Genomics & Functional Genomics; Immunology
8.  Multiplex PCR and Next Generation Sequencing for the Non-Invasive Detection of Bladder Cancer 
PLoS ONE  2016;11(2):e0149756.
Background
Highly sensitive and specific urine-based tests to detect either primary or recurrent bladder cancer have proved elusive to date. Our ever increasing knowledge of the genomic aberrations in bladder cancer should enable the development of such tests based on urinary DNA.
Methods
DNA was extracted from urine cell pellets and PCR used to amplify the regions of the TERT promoter and coding regions of FGFR3, PIK3CA, TP53, HRAS, KDM6A and RXRA which are frequently mutated in bladder cancer. The PCR products were barcoded, pooled and paired-end 2 x 250 bp sequencing performed on an Illumina MiSeq. Urinary DNA was analysed from 20 non-cancer controls, 120 primary bladder cancer patients (41 pTa, 40 pT1, 39 pT2+) and 91 bladder cancer patients post-TURBT (89 cancer-free).
Results
Despite the small quantities of DNA extracted from some urine cell pellets, 96% of the samples yielded mean read depths >500. Analysing only previously reported point mutations, TERT mutations were found in 55% of patients with bladder cancer (independent of stage), FGFR3 mutations in 30% of patients with bladder cancer, PIK3CA in 14% and TP53 mutations in 12% of patients with bladder cancer. Overall, these previously reported bladder cancer mutations were detected in 86 out of 122 bladder cancer patients (70% sensitivity) and in only 3 out of 109 patients with no detectable bladder cancer (97% specificity).
Conclusion
This simple, cost-effective approach could be used for the non-invasive surveillance of patients with non-muscle-invasive bladder cancers harbouring these mutations. The method has a low DNA input requirement and can detect low levels of mutant DNA in a large excess of normal DNA. These genes represent a minimal biomarker panel to which extra markers could be added to develop a highly sensitive diagnostic test for bladder cancer.
doi:10.1371/journal.pone.0149756
PMCID: PMC4762704  PMID: 26901314
9.  Wellington-bootstrap: differential DNase-seq footprinting identifies cell-type determining transcription factors 
BMC Genomics  2015;16:1000.
Background
The analysis of differential gene expression is a fundamental tool to relate gene regulation with specific biological processes. Differential binding of transcription factors (TFs) can drive differential gene expression. While DNase-seq data can provide global snapshots of TF binding, tools for detecting differential binding from pairs of DNase-seq data sets are lacking.
Results
In order to link expression changes with changes in TF binding we introduce the concept of differential footprinting alongside a computational tool. We demonstrate that differential footprinting is associated with differential gene expression and can be used to define cell types by their specific TF occupancy patterns.
Conclusions
Our new tool, Wellington-bootstrap, will enable the detection of differential TF binding facilitating the study of gene regulatory systems.
Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-2081-4) contains supplementary material, which is available to authorized users.
doi:10.1186/s12864-015-2081-4
PMCID: PMC4658755  PMID: 26608661
Transcriptional regulation; Transcription factors binding sites; Digital genomic footprinting; DNase-seq analysis; Gene regulatory networks
10.  Analysis of 5’ gene regions reveals extraordinary conservation of novel non-coding sequences in a wide range of animals 
Background
Phylogenetic footprinting is a comparative method based on the principle that functional sequence elements will acquire fewer mutations over time than non-functional sequences. Successful comparisons of distantly related species will thus yield highly important sequence elements likely to serve fundamental biological roles. RNA regulatory elements are less well understood than those in DNA. In this study we use the emerging model organism Nasonia vitripennis, a parasitic wasp, in a comparative analysis against 12 insect genomes to identify deeply conserved non-coding elements (CNEs) conserved in large groups of insects, with a focus on 5’ UTRs and promoter sequences.
Results
We report the identification of 322 CNEs conserved across a broad range of insect orders. The identified regions are associated with regulatory and developmental genes, and contain short footprints revealing aspects of their likely function in translational regulation. The most ancient regions identified in our analysis were all found to overlap transcribed regions of genes, reflecting stronger conservation of translational regulatory elements than transcriptional elements. Further expanding sequence analyses to non-insect species we also report the discovery of, to our knowledge, the two oldest and most ubiquitous CNE’s yet described in the animal kingdom (700 MYA). These ancient conserved non-coding elements are associated with the two ribosomal stalk genes, RPLP1 and RPLP2, and were very likely functional in some of the earliest animals.
Conclusions
We report the identification of the most deeply conserved CNE’s found to date, and several other deeply conserved elements which are without exception, part of 5’ untranslated regions of transcripts, and occur in a number of key translational regulatory genes, highlighting translational regulation of translational regulators as a conserved feature of insect genomes.
Electronic supplementary material
The online version of this article (doi:10.1186/s12862-015-0499-6) contains supplementary material, which is available to authorized users.
doi:10.1186/s12862-015-0499-6
PMCID: PMC4613772  PMID: 26482678
Conserved non-coding regions; Nasonia vitripennis; Phylogenetic footprinting; Translation regulation; mRNA secondary structures; UTRs
11.  Conserved Cis-Regulatory Modules Control Robustness in Msx1 Expression at Single-Cell Resolution 
Genome Biology and Evolution  2015;7(9):2762-2778.
The process of transcription is highly stochastic leading to cell-to-cell variations and noise in gene expression levels. However, key essential genes have to be precisely expressed at the correct amount and time to ensure proper cellular development and function. Studies in yeast and bacterial systems have shown that gene expression noise decreases as mean expression levels increase, a relationship that is controlled by promoter DNA sequence. However, the function of distal cis-regulatory modules (CRMs), an evolutionary novelty of metazoans, in controlling transcriptional robustness and variability is poorly understood. In this study, we used live cell imaging of transfected reporters combined with a mathematical modelling and statistical inference scheme to quantify the function of conserved Msx1 CRMs and promoters in modulating single-cell real-time transcription rates in C2C12 mouse myoblasts. The results show that the mean expression–noise relationship is solely promoter controlled for this key pluripotency regulator. In addition, we demonstrate that CRMs modulate single-cell basal promoter rate distributions in a graded manner across a population of cells. This extends the rheostatic model of CRM action to provide a more detailed understanding of CRM function at single-cell resolution. We also identify a novel CRM transcriptional filter function that acts to reduce intracellular variability in transcription rates and show that this can be phylogenetically separable from rate modulating CRM activities. These results are important for understanding how the expression of key vertebrate developmental transcription factors is precisely controlled both within and between individual cells.
doi:10.1093/gbe/evv179
PMCID: PMC4607535  PMID: 26342140
single-cell transcription; cis-regulatory module; Msx1; promoter; robustness
12.  Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes 
Acetylenic phosphaalkenes (APAs) are used as a novel type of ligands for the stabilization of gold nanoparticles (AuNP). As demonstrated by a variety of experimental and analytical methods, both structural features of the APA, that is, the P=C as well as the C≡C units are essential for NP stabilization. The presence of intact APAs on the AuNP is demonstrated by surface-enhanced Raman spectroscopy (SERS), and first principle calculations indicate that bonding occurs most likely at defect sites on the Au surface. AuNP-bound APAs are in chemical equilibrium with free APAs in solution, leading to a dynamic behavior that can be explored for facile place-exchange reactions with other types of anchor groups such as thiols or more weakly binding phosphine ligands.
doi:10.1002/anie.201504834
PMCID: PMC4557036  PMID: 26211907
ab initio studies; acetylenic phosphaalkenes; dynamic behavior; gold nanoparticles
13.  Chronic FLT3-ITD Signaling in Acute Myeloid Leukemia Is Connected to a Specific Chromatin Signature 
Cell Reports  2015;12(5):821-836.
Summary
Acute myeloid leukemia (AML) is characterized by recurrent mutations that affect the epigenetic regulatory machinery and signaling molecules, leading to a block in hematopoietic differentiation. Constitutive signaling from mutated growth factor receptors is a major driver of leukemic growth, but how aberrant signaling affects the epigenome in AML is less understood. Furthermore, AML cells undergo extensive clonal evolution, and the mutations in signaling genes are often secondary events. To elucidate how chronic growth factor signaling alters the transcriptional network in AML, we performed a system-wide multi-omics study of primary cells from patients suffering from AML with internal tandem duplications in the FLT3 transmembrane domain (FLT3-ITD). This strategy revealed cooperation between the MAP kinase (MAPK) inducible transcription factor AP-1 and RUNX1 as a major driver of a common, FLT3-ITD-specific gene expression and chromatin signature, demonstrating a major impact of MAPK signaling pathways in shaping the epigenome of FLT3-ITD AML.
Graphical Abstract
Highlights
•FLT3-ITD signaling is associated with a common gene expression signature•FLT3-ITD-specific gene expression is associated with a common chromatin signature•FLT3-ITD AML displays chronic activation of the inducible transcription factor AP-1•AP-1 cooperates with RUNX1 to shape the epigenome of FLT3-ITD AML
Cauchy et al. identify a specific gene expression and regulatory signature associated with aberrant signaling in acute myeloid leukemia with FLT3-ITD mutations. In FLT3-ITD AML, the inducible transcription factor AP-1 is chronically activated and cooperates with RUNX1, shaping the epigenome to transactivate specific target genes.
doi:10.1016/j.celrep.2015.06.069
PMCID: PMC4726916  PMID: 26212328
14.  Phosphorus Centers of Different Hybridization in Phosphaalkene-Substituted Phospholes 
Phosphole-substituted phosphaalkenes (PPAs) of the general formula Mes*P=C(CH3)–(C4H2P(Ph))–R 5 a–c (Mes*=2,4,6-tBu3Ph; R=2-pyridyl (a), 2-thienyl (b), phenyl (c)) have been prepared from octa-1,7-diyne-substituted phosphaalkenes by utilizing the Fagan–Nugent route. The presence of two differently hybridized phosphorus centers (σ2,λ3 and σ3,λ3) in 5 offers the possibility to selectively tune the HOMO–LUMO gap of the compounds by utilizing the different reactivity of the two phosphorus heteroatoms. Oxidation of 5 a–c by sulfur proceeds exclusively at the σ3,λ3-phosphorus atom, thus giving rise to the corresponding thioxophospholes 6 a–c. Similarly, 5 a is selectively coordinated by AuCl at the σ3,λ3-phosphorus atom. Subsequent second AuCl coordination at the σ2,λ3-phosphorus heteroatom results in a dimetallic species that is characterized by a gold–gold interaction that provokes a change in π conjugation. Spectroscopic, electrochemical, and theoretical investigations show that the phosphaalkene and the phosphole both have a sizable impact on the electronic properties of the compounds. The presence of the phosphaalkene unit induces a decrease of the HOMO–LUMO gap relative to reference phosphole-containing π systems that lack a P=C substituent.
doi:10.1002/chem.201402406
PMCID: PMC4506554  PMID: 24890504
conjugation; electronic structure; phosphaalkenes; phosphorus; X-ray diffraction
15.  Identification of a Dynamic Core Transcriptional Network in t(8;21) AML that Regulates Differentiation Block and Self-Renewal 
Cell reports  2014;8(6):1974-1988.
SUMMARY
Oncogenic transcription factors such as RUNX1/ ETO, which is generated by the chromosomal translocation t(8;21), subvert normal blood cell development by impairing differentiation and driving malignant self-renewal. Here, we use digital footprinting and chromatin immunoprecipitation sequencing (ChIP-seq) to identify the core RUNX1/ ETO-responsive transcriptional network of t(8;21) cells. We show that the transcriptional program underlying leukemic propagation is regulated by a dynamic equilibrium between RUNX1/ETO and RUNX1 complexes, which bind to identical DNA sites in a mutually exclusive fashion. Perturbation of this equilibrium in t(8;21) cells by RUNX1/ETO depletion leads to a global redistribution of transcription factor complexes within preexisting open chromatin, resulting in the formation of a transcriptional network that drives myeloid differentiation. Our work demonstrates on a genome-wide level that the extent of impaired myeloid differentiation in t(8;21) is controlled by the dynamic balance between RUNX1/ ETO and RUNX1 activities through the repression of transcription factors that drive differentiation.
Graphical Abstract
doi:10.1016/j.celrep.2014.08.024
PMCID: PMC4487811  PMID: 25242324
16.  Alternative Synthesis and Structures of C-monoacetylenic Phosphaalkenes 
An alternative synthesis of C-monoacetylenic phosphaalkenes trans-Mes*P=C(Me)(C≡CR) (Mes* = 2, 4, 6-tBu3Ph, R = Ph, SiMe3) from C-bromophosphaalkenes cis-Mes*P=C(Me)Br using standard Sonogashira coupling conditions is described. Crystallographic studies confirm cis-trans isomerization of the P=C double bond during Pd-catalyzed cross coupling, leading exclusively to trans-acetylenic phosphaalkenes. Crystallographic studies of all synthesized compounds reveal the extend of π-conjugation over the acetylene and P=C π-systems.
doi:10.1002/zaac.201200324
PMCID: PMC4456767  PMID: 26063932
Phosphaalkenes; Sonogashira coupling; Hay coupling; X-ray crystallography
18.  Identification of a Dynamic Core Transcriptional Network in t(8;21) AML that Regulates Differentiation Block and Self-Renewal 
Cell Reports  2014;8(6):1974-1988.
Summary
Oncogenic transcription factors such as RUNX1/ETO, which is generated by the chromosomal translocation t(8;21), subvert normal blood cell development by impairing differentiation and driving malignant self-renewal. Here, we use digital footprinting and chromatin immunoprecipitation sequencing (ChIP-seq) to identify the core RUNX1/ETO-responsive transcriptional network of t(8;21) cells. We show that the transcriptional program underlying leukemic propagation is regulated by a dynamic equilibrium between RUNX1/ETO and RUNX1 complexes, which bind to identical DNA sites in a mutually exclusive fashion. Perturbation of this equilibrium in t(8;21) cells by RUNX1/ETO depletion leads to a global redistribution of transcription factor complexes within preexisting open chromatin, resulting in the formation of a transcriptional network that drives myeloid differentiation. Our work demonstrates on a genome-wide level that the extent of impaired myeloid differentiation in t(8;21) is controlled by the dynamic balance between RUNX1/ETO and RUNX1 activities through the repression of transcription factors that drive differentiation.
Graphical Abstract
Highlights
•RUNX1/ETO drives a t(8;21)-specific transcriptional network•RUNX1/ETO and RUNX1 dynamically compete for the same genomic sites•RUNX1/ETO targets transcription factor complexes that control differentiation•RUNX1/ETO depletion activates a transcriptional network dominated by C/EBPα
Chromosomal rearrangements generate cancer-specific fusion genes that interfere with cell differentiation. Ptasinska et al. show that the most frequent fusion protein in acute myeloid leukemia (RUNX1/ETO) controls a cancer-propagating transcriptional network by binding to genomic sites in a dynamic equilibrium with wild-type RUNX1. Depletion of RUNX1/ETO installs a differentiation-promoting transcriptional network. Our findings demonstrate that the differentiation block in AML has a dynamic component as its core feature, which might provide a target for cancer-specific differentiation therapy.
doi:10.1016/j.celrep.2014.08.024
PMCID: PMC4487811  PMID: 25242324
19.  A Novel Nodal Enhancer Dependent on Pluripotency Factors and Smad2/3 Signaling Conditions a Regulatory Switch During Epiblast Maturation 
PLoS Biology  2014;12(6):e1001890.
HBE, a newly discovered enhancer element, mediates the influence of pluripotency factors and Activin/Nodal signaling on early Nodal expression in the mouse embryo, and controls the activation of later-acting Nodal enhancers.
During early development, modulations in the expression of Nodal, a TGFβ family member, determine the specification of embryonic and extra-embryonic cell identities. Nodal has been extensively studied in the mouse, but aspects of its early expression remain unaccounted for. We identified a conserved hotspot for the binding of pluripotency factors at the Nodal locus and called this sequence “highly bound element” (HBE). Luciferase-based assays, the analysis of fluorescent HBE reporter transgenes, and a conditional mutation of HBE allowed us to establish that HBE behaves as an enhancer, is activated ahead of other Nodal enhancers in the epiblast, and is essential to Nodal expression in embryonic stem cells (ESCs) and in the mouse embryo. We also showed that HBE enhancer activity is critically dependent on its interaction with the pluripotency factor Oct4 and on Activin/Nodal signaling. Use of an in vitro model of epiblast maturation, relying on the differentiation of ESCs into epiblast stem cells (EpiSCs), revealed that this process entails a shift in the regulation of Nodal expression from an HBE-driven phase to an ASE-driven phase, ASE being another autoregulatory Nodal enhancer. Deletion of HBE in ESCs or in EpiSCs allowed us to show that HBE, although not necessary for Nodal expression in EpiSCs, is required in differentiating ESCs to activate the differentiation-promoting ASE and therefore controls this regulatory shift. Our findings clarify how early Nodal expression is regulated and suggest how this regulation can promote the specification of extra-embryonic precusors without inducing premature differentiation of epiblast cells. More generally, they open new perspectives on how pluripotency factors achieve their function.
Author Summary
In the early mouse embryo, Nodal, a member of the TGFbeta superfamily of signalling proteins, promotes the differentiation of extra-embryonic tissues, as well as tissues within the developing embryo itself. Characterising the regulation of Nodal gene expression is essential to understand how Nodal signals in diverse tissue types and at different stages of embryonic development. Four distinct enhancer sequences have been shown to regulate Nodal expression, although none could account for it in the preimplantation epiblast or in embryonic stem cells. We identified a novel enhancer, HBE, responsible for the earliest aspects of Nodal expression. We show that activation of HBE depends on its interaction with a well-known pluripotency factor called Oct4. HBE itself also controls the activation of at least one other Nodal enhancer. Our findings clarify how early Nodal expression is regulated and reveal how pluripotency factors may control the onset of differentiation in embryonic tissues.
doi:10.1371/journal.pbio.1001890
PMCID: PMC4068991  PMID: 24960041
20.  Wigwams: identifying gene modules co-regulated across multiple biological conditions 
Bioinformatics  2013;30(7):962-970.
Motivation: Identification of modules of co-regulated genes is a crucial first step towards dissecting the regulatory circuitry underlying biological processes. Co-regulated genes are likely to reveal themselves by showing tight co-expression, e.g. high correlation of expression profiles across multiple time series datasets. However, numbers of up- or downregulated genes are often large, making it difficult to discriminate between dependent co-expression resulting from co-regulation and independent co-expression. Furthermore, modules of co-regulated genes may only show tight co-expression across a subset of the time series, i.e. show condition-dependent regulation.
Results: Wigwams is a simple and efficient method to identify gene modules showing evidence for co-regulation in multiple time series of gene expression data. Wigwams analyzes similarities of gene expression patterns within each time series (condition) and directly tests the dependence or independence of these across different conditions. The expression pattern of each gene in each subset of conditions is tested statistically as a potential signature of a condition-dependent regulatory mechanism regulating multiple genes. Wigwams does not require particular time points and can process datasets that are on different time scales. Differential expression relative to control conditions can be taken into account. The output is succinct and non-redundant, enabling gene network reconstruction to be focused on those gene modules and combinations of conditions that show evidence for shared regulatory mechanisms. Wigwams was run using six Arabidopsis time series expression datasets, producing a set of biologically significant modules spanning different combinations of conditions.
Availability and implementation: A Matlab implementation of Wigwams, complete with graphical user interfaces and documentation, is available at: warwick.ac.uk/wigwams.
Contact: k.j.denby@warwick.ac.uk
Supplementary Data: Supplementary data are available at Bioinformatics online.
doi:10.1093/bioinformatics/btt728
PMCID: PMC3967106  PMID: 24351708
21.  Enhanced Photochemical Hydrogen Production by a Molecular Diiron Catalyst Incorporated into a Metal–Organic Framework 
Journal of the American Chemical Society  2013;135(45):16997-17003.
A molecular proton reduction catalyst [FeFe](dcbdt)(CO)6 (1, dcbdt = 1,4-dicarboxylbenzene-2,3-dithiolate) with structural similarities to [FeFe]-hydrogenase active sites has been incorporated into a highly robust Zr(IV)-based metal–organic framework (MOF) by postsynthetic exchange (PSE). The PSE protocol is crucial as direct solvothermal synthesis fails to produce the functionalized MOF. The molecular integrity of the organometallic site within the MOF is demonstrated by a variety of techniques, including X-ray absorption spectroscopy. In conjunction with [Ru(bpy)3]2+ as a photosensitizer and ascorbate as an electron donor, MOF-[FeFe](dcbdt)(CO)6 catalyzes photochemical hydrogen evolution in water at pH 5. The immobilized catalyst shows substantially improved initial rates and overall hydrogen production when compared to a reference system of complex 1 in solution. Improved catalytic performance is ascribed to structural stabilization of the complex when incorporated in the MOF as well as the protection of reduced catalysts 1– and 12– from undesirable charge recombination with oxidized ascorbate.
doi:10.1021/ja407176p
PMCID: PMC3829681  PMID: 24116734
22.  Wellington: a novel method for the accurate identification of digital genomic footprints from DNase-seq data 
Nucleic Acids Research  2013;41(21):e201.
The expression of eukaryotic genes is regulated by cis-regulatory elements such as promoters and enhancers, which bind sequence-specific DNA-binding proteins. One of the great challenges in the gene regulation field is to characterise these elements. This involves the identification of transcription factor (TF) binding sites within regulatory elements that are occupied in a defined regulatory context. Digestion with DNase and the subsequent analysis of regions protected from cleavage (DNase footprinting) has for many years been used to identify specific binding sites occupied by TFs at individual cis-elements with high resolution. This methodology has recently been adapted for high-throughput sequencing (DNase-seq). In this study, we describe an imbalance in the DNA strand-specific alignment information of DNase-seq data surrounding protein–DNA interactions that allows accurate prediction of occupied TF binding sites. Our study introduces a novel algorithm, Wellington, which considers the imbalance in this strand-specific information to efficiently identify DNA footprints. This algorithm significantly enhances specificity by reducing the proportion of false positives and requires significantly fewer predictions than previously reported methods to recapitulate an equal amount of ChIP-seq data. We also provide an open-source software package, pyDNase, which implements the Wellington algorithm to interface with DNase-seq data and expedite analyses.
doi:10.1093/nar/gkt850
PMCID: PMC3834841  PMID: 24071585
23.  A local regulatory network around three NAC transcription factors in stress responses and senescence in Arabidopsis leaves 
The Plant Journal  2013;75(1):26-39.
Summary
A model is presented describing the gene regulatory network surrounding three similar NAC transcription factors that have roles in Arabidopsis leaf senescence and stress responses. ANAC019, ANAC055 and ANAC072 belong to the same clade of NAC domain genes and have overlapping expression patterns. A combination of promoter DNA/protein interactions identified using yeast 1-hybrid analysis and modelling using gene expression time course data has been applied to predict the regulatory network upstream of these genes. Similarities and divergence in regulation during a variety of stress responses are predicted by different combinations of upstream transcription factors binding and also by the modelling. Mutant analysis with potential upstream genes was used to test and confirm some of the predicted interactions. Gene expression analysis in mutants of ANAC019 and ANAC055 at different times during leaf senescence has revealed a distinctly different role for each of these genes. Yeast 1-hybrid analysis is shown to be a valuable tool that can distinguish clades of binding proteins and be used to test and quantify protein binding to predicted promoter motifs.
doi:10.1111/tpj.12194
PMCID: PMC3781708  PMID: 23578292
Arabidopsis thaliana; Botrytis cinerea; NAC transcription factors; gene regulatory network; senescence; stress
24.  Arabidopsis HEAT SHOCK TRANSCRIPTION FACTORA1b overexpression enhances water productivity, resistance to drought, and infection 
Journal of Experimental Botany  2013;64(11):3467-3481.
Heat-stressed crops suffer dehydration, depressed growth, and a consequent decline in water productivity, which is the yield of harvestable product as a function of lifetime water consumption and is a trait associated with plant growth and development. Heat shock transcription factor (HSF) genes have been implicated not only in thermotolerance but also in plant growth and development, and therefore could influence water productivity. Here it is demonstrated that Arabidopsis thaliana plants with increased HSFA1b expression showed increased water productivity and harvest index under water-replete and water-limiting conditions. In non-stressed HSFA1b-overexpressing (HSFA1bOx) plants, 509 genes showed altered expression, and these genes were not over-represented for development-associated genes but were for response to biotic stress. This confirmed an additional role for HSFA1b in maintaining basal disease resistance, which was stress hormone independent but involved H2O2 signalling. Fifty-five of the 509 genes harbour a variant of the heat shock element (HSE) in their promoters, here named HSE1b. Chromatin immunoprecipitation-PCR confirmed binding of HSFA1b to HSE1b in vivo, including in seven transcription factor genes. One of these is MULTIPROTEIN BRIDGING FACTOR1c (MBF1c). Plants overexpressing MBF1c showed enhanced basal resistance but not water productivity, thus partially phenocopying HSFA1bOx plants. A comparison of genes responsive to HSFA1b and MBF1c overexpression revealed a common group, none of which harbours a HSE1b motif. From this example, it is suggested that HSFA1b directly regulates 55 HSE1b-containing genes, which control the remaining 454 genes, collectively accounting for the stress defence and developmental phenotypes of HSFA1bOx.
doi:10.1093/jxb/ert185
PMCID: PMC3733161  PMID: 23828547
Arabidopsis thaliana; basal resistance; biotic and abiotic stress; Brassica napus; drought stress; heat stress; Hyaloperonospora parasitica; hydrogen peroxide; Pseudomonas syringae; transcription factors; water productivity.
25.  New Class of Molecular Conductance Switches Based on the [1,3]-Silyl Migration from Silanes to Silenes 
On the basis of first-principles density functional theory calculations, we propose a new molecular photoswitch which exploits a photochemical [1,3]-silyl(germyl) shift leading from a silane to a silene (a Si=C double bonded compound). The silanes investigated herein act as the OFF state, with tetrahedral saturated silicon atoms disrupting the conjugation through the molecules. The silenes, on the other hand, have conjugated paths spanning over the complete molecules and thus act as the ON state. We calculate ON/OFF conductance ratios in the range of 10–50 at a voltage of +1 V. In the low bias regime, the ON/OFF ratio increases to a range of 200–1150. The reverse reaction could be triggered thermally or photolytically, with the silene being slightly higher in relative energy than the silane. The calculated activation barriers for the thermal back-rearrangement of the migrating group can be tuned and are in the range 108–171 kJ/mol for the switches examined herein. The first-principles calculations together with a simple one-level model show that the high ON/OFF ratio in the molecule assembled in a solid state device is due to changes in the energy position of the frontier molecular orbitals compared to the Fermi energy of the electrodes, in combination with an increased effective coupling between the molecule and the electrodes for the ON state.
doi:10.1021/jp400062y
PMCID: PMC3670211  PMID: 23741530

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