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1.  Effects of Cocaine and Withdrawal on the Mouse Nucleus Accumbens Transcriptome 
Genes, brain, and behavior  2012;12(1):21-33.
Genetic association studies, pharmacological investigations, and analysis of mice lacking individual genes have made it clear that cocaine administration and withdrawal have a profound impact on multiple neurotransmitter systems. The GABAergic medium spiny neurons of the nucleus accumbens (NAc) exhibit changes in the expression of genes encoding receptors for glutamate and in the signaling pathways triggered by dopamine binding to G-protein coupled dopamine receptors. Deep sequence analysis provides a sensitive, quantitative and global analysis of the effects of cocaine on the NAc transcriptome. RNA prepared from the NAc of adult male mice receiving daily injections of saline or cocaine, or cocaine followed by a period of withdrawal, was used for high-throughput sequence analysis. Changes were validated by qPCR or Western blot. Based on pathway analysis, a preponderance of the genes affected by cocaine and withdrawal were involved in the cadherin, heterotrimeric G-protein, and Wnt signaling pathways. Distinct subsets of cadherins and protocadherins exhibited a sustained increase or decrease in expression. Sustained down-regulation of several heterotrimeric G-protein β- and γ-subunits was observed. In addition to altered expression of receptors for small molecule neurotransmitters, neuropeptides and endocannabinoids, changes in the expression of plasma membrane transporters and vesicular neurotransmitter transporters were also observed. The effects of chronic cocaine and withdrawal on the expression of genes essential to cholinergic, glutamatergic, GABAergic, peptidergic, and endocannabinoid signaling are as profound as their effects on dopaminergic transmission. Simultaneous targeting of multiple withdrawal-specific changes in gene expression may facilitate development of new therapeutic approaches that are better able to prevent relapse.
doi:10.1111/j.1601-183X.2012.00873.x
PMCID: PMC3553295  PMID: 23094851
RNA-Seq; pathway analysis; Wnt/cadherin signaling; heterotrimeric G-protein; glutamate; neuropeptide; acetylcholine; GABA
2.  Global Patterns of Tissue-Specific Alternative Polyadenylation in Drosophila 
Cell reports  2012;1(3):277-289.
SUMMARY
We analyzed the usage and consequences of alternative cleavage and polyadenylation (APA) in Drosophila melanogaster by using >1 billion reads of stranded mRNA-seq across a variety of dissected tissues. Beyond demonstrating that a majority of fly transcripts are subject to APA, we observed broad trends for 3′ untranslated region (UTR) shortening in the testis and lengthening in the central nervous system (CNS); the latter included hundreds of unannotated extensions ranging up to 18 kb. Extensive northern analyses validated the accumulation of full-length neural extended transcripts, and in situ hybridization indicated their spatial restriction to the CNS. Genes encoding RNA binding proteins (RBPs) and transcription factors were preferentially subject to 3′ UTR extensions. Motif analysis indicated enrichment of miRNA and RBP sites in the neural extensions, and their termini were enriched in canonical cis elements that promote cleavage and polyadenylation. Altogether, we reveal broad tissue-specific patterns of APA in Drosophila and transcripts with unprecedented 3′ UTR length in the nervous system.
doi:10.1016/j.celrep.2012.01.001
PMCID: PMC3368434  PMID: 22685694
3.  Identification of Functional Elements and Regulatory Circuits by Drosophila modENCODE 
Roy, Sushmita | Ernst, Jason | Kharchenko, Peter V. | Kheradpour, Pouya | Negre, Nicolas | Eaton, Matthew L. | Landolin, Jane M. | Bristow, Christopher A. | Ma, Lijia | Lin, Michael F. | Washietl, Stefan | Arshinoff, Bradley I. | Ay, Ferhat | Meyer, Patrick E. | Robine, Nicolas | Washington, Nicole L. | Di Stefano, Luisa | Berezikov, Eugene | Brown, Christopher D. | Candeias, Rogerio | Carlson, Joseph W. | Carr, Adrian | Jungreis, Irwin | Marbach, Daniel | Sealfon, Rachel | Tolstorukov, Michael Y. | Will, Sebastian | Alekseyenko, Artyom A. | Artieri, Carlo | Booth, Benjamin W. | Brooks, Angela N. | Dai, Qi | Davis, Carrie A. | Duff, Michael O. | Feng, Xin | Gorchakov, Andrey A. | Gu, Tingting | Henikoff, Jorja G. | Kapranov, Philipp | Li, Renhua | MacAlpine, Heather K. | Malone, John | Minoda, Aki | Nordman, Jared | Okamura, Katsutomo | Perry, Marc | Powell, Sara K. | Riddle, Nicole C. | Sakai, Akiko | Samsonova, Anastasia | Sandler, Jeremy E. | Schwartz, Yuri B. | Sher, Noa | Spokony, Rebecca | Sturgill, David | van Baren, Marijke | Wan, Kenneth H. | Yang, Li | Yu, Charles | Feingold, Elise | Good, Peter | Guyer, Mark | Lowdon, Rebecca | Ahmad, Kami | Andrews, Justen | Berger, Bonnie | Brenner, Steven E. | Brent, Michael R. | Cherbas, Lucy | Elgin, Sarah C. R. | Gingeras, Thomas R. | Grossman, Robert | Hoskins, Roger A. | Kaufman, Thomas C. | Kent, William | Kuroda, Mitzi I. | Orr-Weaver, Terry | Perrimon, Norbert | Pirrotta, Vincenzo | Posakony, James W. | Ren, Bing | Russell, Steven | Cherbas, Peter | Graveley, Brenton R. | Lewis, Suzanna | Micklem, Gos | Oliver, Brian | Park, Peter J. | Celniker, Susan E. | Henikoff, Steven | Karpen, Gary H. | Lai, Eric C. | MacAlpine, David M. | Stein, Lincoln D. | White, Kevin P. | Kellis, Manolis
Science (New York, N.Y.)  2010;330(6012):1787-1797.
To gain insight into how genomic information is translated into cellular and developmental programs, the Drosophila model organism Encyclopedia of DNA Elements (modENCODE) project is comprehensively mapping transcripts, histone modifications, chromosomal proteins, transcription factors, replication proteins and intermediates, and nucleosome properties across a developmental time course and in multiple cell lines. We have generated more than 700 data sets and discovered protein-coding, noncoding, RNA regulatory, replication, and chromatin elements, more than tripling the annotated portion of the Drosophila genome. Correlated activity patterns of these elements reveal a functional regulatory network, which predicts putative new functions for genes, reveals stage- and tissue-specific regulators, and enables gene-expression prediction. Our results provide a foundation for directed experimental and computational studies in Drosophila and related species and also a model for systematic data integration toward comprehensive genomic and functional annotation.
doi:10.1126/science.1198374
PMCID: PMC3192495  PMID: 21177974
4.  The Developmental Transcriptome of Drosophila melanogaster 
Nature  2010;471(7339):473-479.
Drosophila melanogaster is one of the most well studied genetic model organisms, nonetheless its genome still contains unannotated coding and non-coding genes, transcripts, exons, and RNA editing sites. Full discovery and annotation are prerequisites for understanding how the regulation of transcription, splicing, and RNA editing directs development of this complex organism. We used RNA-Seq, tiling microarrays, and cDNA sequencing to explore the transcriptome in 30 distinct developmental stages. We identified 111,195 new elements, including thousands of genes, coding and non-coding transcripts, exons, splicing and editing events and inferred protein isoforms that previously eluded discovery using established experimental, prediction and conservation-based approaches. Together, these data substantially expand the number of known transcribed elements in the Drosophila genome and provide a high-resolution view of transcriptome dynamics throughout development.
doi:10.1038/nature09715
PMCID: PMC3075879  PMID: 21179090
5.  Genomewide characterization of non-polyadenylated RNAs 
Genome Biology  2011;12(2):R16.
Background
RNAs can be physically classified into poly(A)+ or poly(A)- transcripts according to the presence or absence of a poly(A) tail at their 3' ends. Current deep sequencing approaches largely depend on the enrichment of transcripts with a poly(A) tail, and therefore offer little insight into the nature and expression of transcripts that lack poly(A) tails.
Results
We have used deep sequencing to explore the repertoire of both poly(A)+ and poly(A)- RNAs from HeLa cells and H9 human embryonic stem cells (hESCs). Using stringent criteria, we found that while the majority of transcripts are poly(A)+, a significant portion of transcripts are either poly(A)- or bimorphic, being found in both the poly(A)+ and poly(A)- populations. Further analyses revealed that many mRNAs may not contain classical long poly(A) tails and such messages are overrepresented in specific functional categories. In addition, we surprisingly found that a few excised introns accumulate in cells and thus constitute a new class of non-polyadenylated long non-coding RNAs. Finally, we have identified a specific subset of poly(A)- histone mRNAs, including two histone H1 variants, that are expressed in undifferentiated hESCs and are rapidly diminished upon differentiation; further, these same histone genes are induced upon reprogramming of fibroblasts to induced pluripotent stem cells.
Conclusions
We offer a rich source of data that allows a deeper exploration of the poly(A)- landscape of the eukaryotic transcriptome. The approach we present here also applies to the analysis of the poly(A)- transcriptomes of other organisms.
doi:10.1186/gb-2011-12-2-r16
PMCID: PMC3188798  PMID: 21324177
6.  RNA-Guided RNA Cleavage by a CRISPR RNA-Cas Protein Complex 
Cell  2009;139(5):945-956.
SUMMARY
Compelling evidence indicates that the CRISPR-Cas system protects prokaryotes from viruses and other potential genome invaders. This adaptive prokaryotic immune system arises from the clustered regularly interspaced short palindromic repeats (CRISPRs) found in prokaryotic genomes, which harbor short invader-derived sequences, and the CRISPR-associated (Cas) protein-coding genes. Here we have identified a CRISPR-Cas effector complex that is comprised of small invader-targeting RNAs from the CRISPR loci (termed prokaryotic silencing (psi)RNAs) and the RAMP module (or Cmr) Cas proteins. The psiRNA-Cmr protein complexes cleave complementary target RNAs at a fixed distance from the 3' end of the integral psiRNAs. In Pyrococcus furiosus, psiRNAs occur in two size forms that share a common 5' sequence tag but have distinct 3' ends that direct cleavage of a given target RNA at two distinct sites. Our results indicate that prokaryotes possess a unique RNA silencing system that functions by homology-dependent cleavage of invader RNAs.
doi:10.1016/j.cell.2009.07.040
PMCID: PMC2951265  PMID: 19945378
7.  Dopamine, uncertainty and TD learning 
Substantial evidence suggests that the phasic activities of dopaminergic neurons in the primate midbrain represent a temporal difference (TD) error in predictions of future reward, with increases above and decreases below baseline consequent on positive and negative prediction errors, respectively. However, dopamine cells have very low baseline activity, which implies that the representation of these two sorts of error is asymmetric. We explore the implications of this seemingly innocuous asymmetry for the interpretation of dopaminergic firing patterns in experiments with probabilistic rewards which bring about persistent prediction errors. In particular, we show that when averaging the non-stationary prediction errors across trials, a ramping in the activity of the dopamine neurons should be apparent, whose magnitude is dependent on the learning rate. This exact phenomenon was observed in a recent experiment, though being interpreted there in antipodal terms as a within-trial encoding of uncertainty.
doi:10.1186/1744-9081-1-6
PMCID: PMC1171969  PMID: 15953384

Results 1-7 (7)