Invertebrate and vertebrate vestigial (vg) and vestigial-like (vgl) genes are involved in embryonic patterning and cell fate determination. These genes encode cofactors that interact with members of the TEAD/Scalloped family of transcription factors and modulate their activity. We have previously shown that, in mice, Vgll2 is differentially expressed in the developing facial prominences. In this study, we show that the zebrafish ortholog vgll2a is expressed in the pharyngeal endoderm and ectoderm surrounding the neural crest derived mesenchyme of the pharyngeal arches. Moreover, both the FGF and retinoic acid (RA) signaling pathways, which are critical components of the hierarchy controlling craniofacial patterning, regulate this domain of vgll2a expression. Consistent with these observations, vgll2a is required within the pharyngeal endoderm for NCC survival and pharyngeal cartilage development. Specifically, knockdown of Vgll2a in zebrafish embryos using Morpholino injection results in increased cell death within the pharyngeal arches, aberrant endodermal pouch morphogenesis, and hypoplastic cranial cartilages. Overall, our data reveal a novel non-cell autonomous role for Vgll2a in development of the NCC-derived vertebrate craniofacial skeleton.
Vestigial-like; Vgl-2; VITO-1; craniofacial; zebrafish; FGF; Retinoic Acid; Cell Death
Four members of the TEAD/TEF family of transcription factors are expressed widely in mouse embryos and adult tissues. Although in vitro studies have suggested various roles for TEAD proteins, their in vivo functions remain poorly understood. Here we examined the role of Tead genes by generating mouse mutants for Tead1 and Tead2. Tead2−/− mice appeared normal, but Tead1−/−; Tead2−/− embryos died at embryonic day 9.5 (E9.5) with severe growth defects and morphological abnormalities. At E8.5, Tead1−/−; Tead2−/− embryos were already small and lacked characteristic structures such as a closed neural tube, a notochord, and somites. Despite these overt abnormalities, differentiation and patterning of the neural plate and endoderm were relatively normal. In contrast, the paraxial mesoderm and lateral plate mesoderm were displaced laterally, and a differentiated notochord was not maintained. These abnormalities and defects in yolk sac vasculature organization resemble those of mutants for Yap, which encodes a coactivator of TEAD proteins. Moreover, we demonstrated genetic interactions between Tead1 and Tead2 and Yap. Finally, Tead1−/−; Tead2−/− embryos showed reduced cell proliferation and increased apoptosis. These results suggest that Tead1 and Tead2 are functionally redundant, use YAP as a major coactivator, and support notochord maintenance as well as cell proliferation and survival in mouse development.
Vertebrate development requires the activity of the myocyte enhancer factor 2 (mef2) gene family for muscle cell specification and subsequent differentiation. Additionally, several muscle-specific functions of MEF2 family proteins require binding additional cofactors including members of the Transcription Enhancing Factor-1 (TEF-1) and Vestigial-like protein families. In Drosophila there is a single mef2 (Dmef2) gene as well single homologues of TEF-1 and vestigial-like, scalloped (sd), and vestigial (vg), respectively. To clarify the role(s) of these factors, we examined the requirements for Vg and Sd during Drosophila muscle specification. We found that both are required for muscle differentiation as loss of sd or vg leads to a reproducible loss of a subset of either cardiac or somatic muscle cells in developing embryos. This muscle requirement for Sd or Vg is cell specific, as ubiquitous overexpression of either or both of these proteins in muscle cells has a deleterious effect on muscle differentiation. Finally, using both in vitro and in vivo binding assays, we determined that Sd, Vg, and Dmef2 can interact directly. Thus, the muscle-specific phenotypes we have associated with Vg or Sd may be a consequence of alternative binding of Vg and/or Sd to Dmef2 forming alternative protein complexes that modify Dmef2 activity.
The TEAD (1–4) transcription factors comprise the conserved TEA/ATTS DNA-binding domain recognising the MCAT element in the promoters of muscle-specific genes. Despite extensive genetic analysis, the function of TEAD factors in muscle differentiation has proved elusive due to redundancy among the family members. Expression of the TEA/ATTS DNA-binding domain that acts as a dominant negative repressor of TEAD factors in C2C12 myoblasts inhibits their differentiation, whereas selective shRNA knockdown of TEAD4 results in abnormal differentiation characterised by the formation of shortened myotubes. Chromatin immunoprecipitation coupled to array hybridisation shows that TEAD4 occupies 867 promoters including those of myogenic miRNAs. We show that TEAD factors directly induce Myogenin, CDKN1A and Caveolin 3 expression to promote myoblast differentiation. RNA-seq identifies a set of genes whose expression is strongly reduced upon TEAD4 knockdown among which are structural and regulatory proteins and those required for the unfolded protein response. In contrast, TEAD4 represses expression of the growth factor CTGF (connective tissue growth factor) to promote differentiation. Together these results show that TEAD factor activity is essential for normal C2C12 cell differentiation and suggest a role for TEAD4 in regulating expression of the unfolded protein response genes.
MYOD1; ER-stress; myoblast fusion; Chromatin immunoprecipitation; RNA-seq
TEAD1 (TEA domain family member 1) is constitutively expressed in cardiac and skeletal muscles. It acts as a key molecule of muscle development, and trans-activates multiple target genes involved in cell proliferation and differentiation pathways. However, its target genes in skeletal muscles, regulatory mechanisms and networks are unknown.
In this paper, we have identified 136 target genes regulated directly by TEAD1 in skeletal muscle using integrated analyses of ChIP-on-chip. Most of the targets take part in the cell process, physiology process, biological regulation metabolism and development process. The targets also play an important role in MAPK, mTOR, T cell receptor, JAK-STAT, calcineurin and insulin signaling pathways. TEAD1 regulates foxo3a transcription through binding to the M-CAT element in foxo3a promoter, demonstrated with independent ChIP-PCR, EMSA and luciferase reporter system assay. In addition, results of over-expression and inhibition experiments suggest that foxo3a is positively regulated by TEAD1.
Our present data suggests that TEAD1 plays an important role in the regulation of gene expression and different signaling pathways may co-operate with each other mediated by TEAD1. We have preliminarily concluded that TEAD1 may regulate FoxO3a expression through calcineurin/MEF2/NFAT and IGF-1/PI3K/AKT signaling pathways in skeletal muscles. These findings provide important clues for further analysis of the role of FoxO3a gene in the formation and transformation of skeletal muscle fiber types.
The expression of several muscle-specific genes is partially or completely regulated by MCAT elements, which bind members of the TEF family of transcription factors. TEF1 itself is unable to activate reporter plasmids bearing TEF1-binding sites, suggesting that additional bridging or co-activating factors are necessary to allow interaction of TEF1 with the transcriptional machinery. In addition, none of the known TEF genes are exclusively expressed in the cardiac or skeletal muscle lineage to account for the muscle-specific expression of MCAT-dependent genes. Here we describe that VITO-1, a new SID (scalloped interaction domain)-containing protein, binds to TEF1 in vitro and strongly stimulates transcription of a MCAT reporter plasmid together with TEF-1. Since VITO-1 is predominantly expressed in the skeletal muscle lineage, it might serve as an essential transcriptional intermediary factor to promote muscle-specific expression via MCAT cis-regulatory elements. Although VITO-1 alone is not sufficient to initiate myogenic conversion of 10T1/2 fibroblastic cells, it enhanced MyoD-mediated myogenic conversion. In addition, interference with VITO-1 expression by siRNA attenuated differentiation of C2C12 muscle cells and MyoD-dependent myogenesis in 10T1/2 cells. We conclude that VITO-1 is a crucial new cofactor of the muscle regulatory programme.
The Hippo (Hpo) signaling pathway controls cell growth, proliferation and apoptosis in both Drosophila and vertebrates. In Drosophila, Hpo signaling regulates gene expression by inhibiting a transcription complex consisting of the transcriptional coactivator Yorkie (Yki) and the TEAD/TEF family of transcription factor Scalloped (Sd). Here we provide genetic evidence that both isoforms of 14-3-3, 14-3-3ε and 14-3-3ζ, regulate Yki activity through modulating its subcellular localization. Inactivation of 14-3-3 by RNAi or genetic mutations enhanced whereas overexpression of 14-3-3 suppressed tissue overgrowth induced by Yki overexpression. Loss of 14-3-3 resulted in the accumulation of Yki in the nucleus. We found that regulation of Yki by 14-3-3 was mediated by phosphorylation of Yki at S168. In addition, we found that Hpo signaling also inhibited Yki nuclear localization and activity by phosphorylating Yki at S111 and S250, and this inhibition appears to be independent of 14-3-3. Finally, we provided evidence that Hpo signaling restricted Yki nuclear localization depending on CRM1-mediated nuclear export.
The interferon inducible transmembrane (IFITM) proteins mediate several cellular processes such as homotypic cell adhesion functions of interferons (IFNs) and cellular anti-proliferative activities. We show that the BAF complex mediated induction of IFITM3 is dependent on binding of the transcriptional enhancer factor 1 (TEF-1/TEAD1) to the M-CAT like elements of its promoter. TEF-1 knock-down reduced the BAF complex mediated activation of IFITM3 promoter. In the absence of the BAF complex, TEF-1 is repressive to IFITM3 expression. The regulation of IFITM3 by TEF-1 demonstrates that TEF-1 dependent regulation is more widespread than its previously established role in the expression of muscle specific genes.
The Drosophila member of the vestigial-like gene family (vestigial) is known primarily as a transcriptional activator that defines cell identity during Drosophila wing differentiation. We show that during embryo development Vestigial also has a role during specification of muscle–muscle attachments in ventral longitudinal muscles.
The somatic muscles of Drosophila develop in a complex pattern that is repeated in each embryonic hemi-segment. During early development, progenitor cells fuse to form a syncytial muscle, which further differentiates via expression of muscle-specific factors that induce specific responses to external signals to regulate late-stage processes such as migration and attachment. Initial communication between somatic muscles and the epidermal tendon cells is critical for both of these processes. However, later establishment of attachments between longitudinal muscles at the segmental borders is largely independent of the muscle–epidermal attachment signals, and relatively little is known about how this event is regulated. Using a combination of null mutations and a truncated version of Sd that binds Vg but not DNA, we show that Vestigial (Vg) is required in ventral longitudinal muscles to induce formation of stable intermuscular attachments. In several muscles, this activity may be independent of Sd. Furthermore, the cell-specific differentiation events induced by Vg in two cells fated to form attachments are coordinated by Drosophila epidermal growth factor signaling. Thus, Vg is a key factor to induce specific changes in ventral longitudinal muscles 1–4 identity and is required for these cells to be competent to form stable intermuscular attachments with each other.
TEAD proteins are transcription factors that are crucial for development, but also play a role in cancers. Several developmentally and pathologically important genes are upregulated by TEADs. TEADs have a TEA domain that enables them to bind specific DNA elements and a transactivation domain that enables them to interact with coactivators. TEADs on their own are unable to activate transcription and they require the help of coactivators. Several TEAD-interacting coactivators are known and they can be classified into three groups: (1) YAP and its paralog TAZ; (2) Vgll proteins; and (3) p160s. Accordingly, these coactivators also play a role in development and cancers. Recent studies have shown that TEADs and their coactivators aid in the progression of various cancers, including the difficult to treat glioblastoma, liver and ovarian cancers. They facilitate cancer progression through expression of proliferation promoting genes such as c-myc, survivin, Axl, CTGF and Cyr61. There is also a good correlation between high TEAD or its coactivator expression and poor prognosis in various cancers. Given the fact that TEADs and their coactivators need to work together for a functional outcome, disrupting the interaction between them appears to be a viable option for cancer therapy. Structures of TEAD-coactivator complexes have been elucidated and will facilitate drug design and development.
YAP; TAZ; Vgll proteins; TEAD; cancer
Epithelial neoplasias are associated with alterations in cell polarity and excessive cell proliferation, yet how these neoplastic properties are related to one another is still poorly understood. The study of Drosophila genes that function as neoplastic tumor suppressors by regulating both of these properties has significant potential to clarify this relationship.
Here we show in Drosophila that loss of Scribbled (Scrib), a cell polarity regulator and neoplastic tumor suppressor, results in impaired Hippo pathway signaling in the epithelial tissues of both the eye and wing imaginal disc. scrib mutant tissue overgrowth, but not the loss of cell polarity, is dependent upon defective Hippo signaling and can be rescued by knockdown of either the TEAD/TEF family transcription factor Scalloped or the transcriptional coactivator Yorkie in the eye disc, or reducing levels of Yorkie in the wing disc. Furthermore, loss of Scrib sensitizes tissue to transformation by oncogenic Ras-Raf signaling, and Yorkie-Scalloped activity is required to promote this cooperative tumor overgrowth. The inhibition of Hippo signaling in scrib mutant eye disc clones is not dependent upon JNK activity, but can be significantly rescued by reducing aPKC kinase activity, and ectopic aPKC activity is sufficient to impair Hippo signaling in the eye disc, even when JNK signaling is blocked. In contrast, warts mutant overgrowth does not require aPKC activity. Moreover, reducing endogenous levels of aPKC or increasing Scrib or Lethal giant larvae levels does not promote increased Hippo signaling, suggesting that aPKC activity is not normally rate limiting for Hippo pathway activity. Epistasis experiments suggest that Hippo pathway inhibition in scrib mutants occurs, at least in part, downstream or in parallel to both the Expanded and Fat arms of Hippo pathway regulation.
Loss of Scrib promotes Yorkie/Scalloped-dependent epithelial tissue overgrowth, and this is also important for driving cooperative tumor overgrowth with oncogenic Ras-Raf signaling. Whether this is also the case in human cancers now warrants investigation since the cell polarity function of Scrib and its capacity to restrain oncogene-mediated transformation, as well as the tissue growth control function of the Hippo pathway, are conserved in mammals.
The Hippo (Hpo) signaling pathway governs cell growth, proliferation, and apoptosis by controlling key regulatory genes that execute these processes; however, the transcription factor of the pathway has remained elusive. Here we provide evidence that the TEAD/TEF family transcription factor Scalloped (Sd) acts together with the coactivator Yorkie (Yki) to regulate Hpo pathway-responsive genes. Sd and Yki form a transcriptional complex whose activity is inhibited by Hpo signaling. Sd overexpression enhances whereas its inactivation suppresses tissue overgrowth caused by Yki overexpression or tumor suppressor mutations in the Hpo pathway. Inactivation of Sd diminishes Hpo target gene expression and reduces organ size whereas a constitutively active Sd promotes tissue overgrowth. Sd promotes Yki nuclear localization whereas Hpo signaling retains Yki in the cytoplasm by phosphorylating Yki at S168. Finally, Sd recruits Yki to the enhancer of a pathway-responsive gene diap1, suggesting that diap1 is a direct transcriptional target of the Hpo pathway.
Multiple KH-domain proteins, collectively known as vigilins, are evolutionarily highly conserved proteins that are present in eukaryotic organisms from yeast to metazoa. Proposed roles for vigilins include chromosome segregation, messenger RNA (mRNA) metabolism, translation and tRNA transport. As a step toward understanding its biological function, we have identified the fission yeast vigilin, designated Vgl1, and have investigated its role in cellular response to environmental stress. Unlike its counterpart in Saccharomyces cerevisiae, we found no indication that Vgl1 is required for the maintenance of cell ploidy in Schizosaccharomyces pombe. Instead, Vgl1 is required for cell survival under thermal stress, and vgl1Δ mutants lose their viability more rapidly than wild-type cells when incubated at high temperature. As for Scp160 in S. cerevisiae, Vgl1 bound polysomes accumulated at endoplasmic reticulum (ER) but in a microtubule-independent manner. Under thermal stress, Vgl1 is rapidly relocalized from the ER to cytoplasmic foci that are distinct from P-bodies but contain stress granule markers such as poly(A)-binding protein and components of the translation initiation factor eIF3. Together, these observations demonstrated in S. pombe the presence of RNA granules with similar composition as mammalian stress granules and identified Vgl1 as a novel component that required for cell survival under thermal stress.
TEAD2, one of the first transcription factors expressed at the beginning of mammalian development, appears to be required during neural development. For example, Tead2 expression is greatest in the dorsal neural crest where it appears to regulate expression of Pax3, a gene essential for brain development. Consistent with this hypothesis, we found that inactivation of the Tead2 gene in mice significantly increased the risk of exencephaly (a defect in neural tube closure). However, none of the embryos exhibited spina bifida, the major phenotype of Pax3 nullizygous embryos, and expression of Pax3 in E11.5 Tead2 nullizygous embryos was normal. Thus, Tead2 plays a role in neural tube closure that is independent of its putative role in Pax3 regulation. In addition, the risk of exencephaly was greatest with Tead2 nullizygous females, and could be suppressed either by folic acid or pifithrin-α. These results reveal a maternal genetic contribution to neural tube closure, and suggest that Tead2-deficient mice provide a model for anencephaly, a common human birth defect that can be prevented by folic acid. genesis 45:577–587, 2007.
exencephaly; anencephaly; TEAD; Pax3; fetal brain
We studied clinical phenotyping and TEAD1 expression in mice and humans to gain a better understanding of the primary origin in the pathogenesis of circumpapillary dysgenesis of the pigment epithelium.
Observational case series and experimental study.
Three female patients from an affected family were included for phenotypic study. Mice and human tissues were used for biochemistry and immunohistochemistry studies.
We performed genetic analyses and longitudinal clinical, imaging, and electrophysiologic studies in a 3-generation family. Western blotting and immunohistochemistry were used to detect TEAD1 expression in mice and human retinal tissues.
Main Outcome Measures
Autofluorescence and optical coherence tomography (OCT) imaging were compared and reviewed from 3 patients. TEAD1 expression was compared in different tissues from mice and human samples.
A point mutation at T1261 in TEAD1 was detected in the mother. Autofluorescence and OCT imaging studies revealed choroid is involved earlier than retinal pigment epithelium (RPE). From immunoblot analysis, we discovered that TEAD1 and its cofactors YAP65 and FOXA2 are expressed in the choroid. Immunohistochemical analysis on frozen sections of mouse retina supports immunoblot results.
The primary cellular origin of circumpapillary dysgenesis of the pigment epithelium is within the choroid instead of the pigment epithelium. The loss of the RPE and photoreceptors in later stages of the disease is a secondary consequence of choroidal degeneration. Studies of the downstream targets of TEAD1 in choroidal cells will provide promising new research opportunities for the development of treatments for choroidal diseases.
This study compared the expression of genes involved in pluripotency, segregation of inner cell mass (ICM) and trophectoderm (TE), and primitive endoderm (PE) formation in porcine embryos produced by in vitro fertilization (IVF), parthenogenetic activation (PA), and nuclear transfer (NT) using either fetal fibroblasts (FF-NT) or mesenchymal stem cells (MSC-NT).
Blastocyst formation and total cell number were analyzed. The expression patterns of transcripts, including SRY-related HMG-box gene 2 (SOX2), reduced expression gene 1 (REX1/ZFP42), LIN28, caudal type homeobox 2 (CDX2), TEA domain family member 4 (TEAD4), integrin beta 1 (ITGB1) and GATA6 were assessed at the 4–8 cell and blastocyst stage embryos by real-time PCR.
Developmental rates to blastocyst stage and total cell number were higher in IVF and PA embryos than in NT embryos. But MSC-NT embryos had increased blastocyst formation and higher total cell number compared to FF-NT embryos. The relative expressions of transcripts were higher in blastocysts than in 4–8 cell stage embryos. The mRNA expression levels of SOX2 and REX1 were largely similar in embryos of different origins. However, the genes such as LIN28, CDX2, TEAD4, ITGB1 and GATA6 showed the differential expression pattern in PA and NT embryos compared to IVF embryos. Importantly, the transcript levels in MSC-NT embryos were relatively less variable to IVF than those in FF-NT embryos.
MSCs seem to be better donors for porcine NT as they improved the developmental competency, and influenced the expression pattern of genes quite similar with IVF embryos than that of FFs.
Gene expression; Preimplantation embryos; Nuclear transfer; Porcine
Although significant effort is expended on identifying transcripts/proteins that are up-regulated in cancer, there are few reports on systematic elucidation of transcriptional mechanisms underlying such druggable cancer-specific targets. The mesothelin (MSLN) gene offers a promising subject, being expressed in a restricted pattern normally, yet highly overexpressed in almost one-third of human malignancies and a target of cancer immunotherapeutic trials. CanScript, a cis promoter element, appears to control MSLN cancer-specific expression; its related genomic sequences may up-regulate other cancer markers. CanScript is a 20-nt bipartite element consisting of an SP1-like motif and a consensus MCAT sequence. The latter recruits TEAD (TEA domain) family members, which are universally expressed. Exploration of the active CanScript element, especially the proteins binding to the SP1-like motif, thus could reveal cancer-specific features having diagnostic or therapeutic interest. The effcient identification of sequence-specific DNA-binding proteins at a given locus, however, has lagged in biomarker explorations. We used two orthogonal proteomics approaches— unbiased SILAC (stable isotope labeling by amino acids in cell culture)/DNA affnity-capture/mass spectrometry survey (SD-MS) and a large transcription factor protein microarray (TFM)—and functional validation to explore systematically the CanScript interactome. SD-MS produced nine candidates, and TFM, 18. The screens agreed in confirming binding by TEAD proteins and by newly identified NAB1 and NFATc. Among other identified candidates, we found functional roles for ZNF24, NAB1 and RFX1 in MSLN expression by cancer cells. Combined interactome screens yield an effcient, reproducible, sensitive, and unbiased approach to identify sequence-specific DNA-binding proteins and other participants in disease-specific DNA elements.
mesothelin; SILAC; protein microarray; ZNF24; NAB1
In Piedmontese cattle the double-muscled phenotype is an inherited condition associated to a point mutation in the myostatin (MSTN) gene. The Piedmontese MSTN missense mutation G938A is translated to C313Y myostatin protein. This mutation alters MSTN function as a negative regulator of muscle growth, thereby inducing muscle hypertrophy. MiRNAs could play a role in skeletal muscle hypertrophy modulation by down-regulating gene expression.
After identifying a 3′-UTR consensus sequence of several negative and positive modulator genes involved in the skeletal muscle hypertrophy pathway, such as IGF1, IGF1R, PPP3CA, NFATc1, MEF2C, GSK3b, TEAD1 and MSTN, we screened miRNAs matching to it. This analysis led to the identification of miR-27b, miR-132, miR-186 and miR-199b-5p as possible candidates. We collected samples of longissimus thoracis from twenty Piedmontese and twenty Friesian male bovines. In Piedmontese group miR-27b was up-regulated 7.4-fold (p < 0.05). Further, we report that the level of MSTN mRNA was about 5-fold lower in Piedmontese cattle vs Friesian cattle (p < 0.0001) and that less mature MSTN protein was detected in the Piedmontese one (p < 0.0001). Cotransfection of miR-27b and psi-check2 vector with the luciferase reporter gene linked to the bovine wild-type 3′-UTR of MSTN strongly inhibited the luciferase activity (79%, p < 0.0001).
These data demonstrate that bovine MSTN is a specific target of miR-27b and that miRNAs contribute to explain additive phenotypic hypertrophy in Piedmontese cattle selected for the MSTN gene mutation, possibly outlining a more precise genetic signature able to elucidate differences in muscle conformation.
MicroRNA; Bovine; Skeletal muscle; Hypertrophy
The TEF (transcriptional enhancer factor) multigene family is primarily functional in muscle-specific genes through binding to MCAT elements that activate or repress transcription of many genes in response to physiological and pathological stimuli. Among the TEF family, TEF-1, RTEF-1 and DTEF-1 are critical regulators of cardiac and smooth muscle-specific genes during cardiovascular development and cardiac disorders including cardiac hypertrophy. Emerging evidence suggests that in addition to functioning as muscle specific transcription factors, members of the TEF family may be key mediators of gene expression induced by hypoxia in endothelial cells by virtue of its multi-domain organization, potential for posttranslational modifications and interactions with numerous transcription factors, which represent a cell-selective control mediator of nuclear signaling. We will briefly review the recent literature demonstrating the involvement of the TEF-family of transcription factors in the regulation of differential gene expression in cardiovascular physiology and pathology.
The SRY (sex determining region Y)-box 11 (SOX11) gene, located on chromosome 2p25, encodes for a transcription factor that is involved in tissue remodeling during embryogenesis and is crucial for neurogenesis. The role for SOX11 in hematopoiesis has not yet been defined. Two genes under direct control of SOX11 are the class- III β-tubulin gene (TUBB3) in neural cells and the transcription factor TEA domain family member 2 (TEAD2) in neural and mesenchymal progenitor cells. Normal, mature lymphocytes lack SOX11 but express SOX4, another member of the same group of SOX transcription factors. We and others recently identified SOX11 as aberrantly expressed in mantle cell lymphoma (MCL). Since SOX11 is variably expressed in MCL it may not be essential for tumorigenesis, but may carry prognostic information. Currently, no specific functional effects have been linked to SOX11 expression in MCL and it is not known which genes are under influence of SOX11 in lymphoma. In this study we found variable expression of SOX11, SOX4 and SOX12 mRNA in mantle cell lymphoma cell lines. Downregulation of SOX11 expression by siRNA verified that SOX11 controlled the expression of the gene TUBB3 in the MCL cell line Granta 519. Furthermore we identified, by global gene expression analysis, 26 new target genes influenced by siRNA SOX11 downmodulation. Among these genes, DBN1, SETMAR and HIG2 were found to be significantly correlated to SOX11 expression in two cohorts of primary mantle cell lymphomas. Chromatin immunoprecipitation (ChIP) analysis showed that these genes are direct targets of the SOX11 protein. In spite of almost complete downregulation of the SOX11 protein no significant effects on Granta 519 cell proliferation or survival in short term in vitro experiments was found. In summary we have identified a number of genes influenced by SOX11 expression in MCL cell lines and primary MCL. Among these genes, DBN1, SETMAR and HIG2 are direct transcriptional targets of the SOX11 protein.
Forced overexpression of TEAD1 in human uterine fibroblast (HUF) and human endometrial stromal cells markedly inhibited prolactin promoter activity in both cell types in a dose-dependent manner, with maximal inhibition of greater than 90%. Conversely, the knockdown of TEAD1 expression in HUF cells with a TEAD1 siRNA resulted in a 75–80% increase in prolactin mRNA levels (P<0.01) compared to control cells exposed to a scrambled nonsense RNA. Mutagenesis of the putative TEAD site inhibited basal promoter activity by about 80%. However, mutagenesis of the TEAD site did not prevent TEAD1-induced inhibition of promoter activity; and the transcription activity of a minimal promoter fragment lacking a putative TEAD binding site was repressed by overexpression of TEAD1. Taken together, these findings suggest that the TEAD binding site on the prolactin promoter is important for the maintenance of basal prolactin promoter activity and that overexpression of TEAD1 has a dominant-negative effect on prolactin promoter activity, probably by interacting directly with other transcription factors.
transcription; gene regulation; siRNA; (human decidua)
Dystrophin/dystrobrevin superfamily proteins play structural and signalling roles at the plasma membrane of many cell types. Defects in them or the associated multiprotein complex cause a range of neuromuscular disorders. Members of the dystrophin branch of the family form heterodimers with members of the dystrobrevin branch, mediated by their coiled-coil domains. To determine which combinations of these proteins might interact during embryonic development, we set out to characterise the gene expression pattern of dystrophin and dystrobrevin family members in zebrafish. γ-dystrobrevin (dtng), a novel dystrobrevin recently identified in fish, is the predominant form of dystrobrevin in embryonic development. Dtng and dmd (dystrophin) have similar spatial and temporal expression patterns in muscle, where transcripts are localized to the ends of differentiated fibres at the somite borders. Dtng is expressed in the notochord while dmd is expressed in the chordo-neural hinge and then in floor plate and hypochord. In addition, dtng is dynamically expressed in rhombomeres 2 and 4-6 of the hindbrain and in the ventral midbrain. α-dystrobrevin (dtna) is expressed widely in the brain with particularly strong expression in the hypothalamus and the telencephalon; drp2 is also expressed widely in the brain. Utrophin expression is found in early pronephros and lateral line development and utrophin and dystrophin are both expressed later in the gut. β-dystrobrevin (dtnb) is expressed in the pronephric duct and widely at low levels. In summary, we find clear instances of co-expression of dystrophin and dystrobrevin family members in muscle, brain and pronephric duct development and many examples of strong and specific expression of members of one family but not the other, an intriguing finding given the presumed heterodimeric state of these molecules.
muscle; zebrafish; notochord; midbrain; rhombomere; gene expression; utrophin; dystrophin; dystrobrevin; drp2; dystrotelin
Investigation of the regulatory region of mTEAD-2, a gene expressed at the beginning of mouse pre-implantation development, led to the surprising discovery of another gene only 3.8 kb upstream of mTEAD-2. Here we show that this new gene is a single copy, testis-specific gene called Soggy (mSgy) that produces a single, dominant mRNA ∼1.3 kb in length. It is transcribed in the direction opposite to mTEAD-2, thus placing the regulatory elements of these two genes in close proximity. mSgy contains three methionine codons that could potentially act as translation start sites, but most mSGY protein synthesis in vitro was initiated from the first Met codon to produce a full-length protein, suggesting that mSGY normally consists of 230 amino acids (26.7 kDa). Transcription began at a cluster of nucleotides ∼150 bp upstream of the first Met codon using a TATA-less promoter contained within the first 0.9 kb upstream. The activity of this promoter was repressed by upstream sequences between –0.9 and –2.5 kb in cells that did not express mSgy, but this repression was relieved in cells that did express mSgy. mSgy mRNA was detected in embryos only after day 15 and in adult tissues only in the developing spermatocytes of seminiferous tubules, suggesting that mSgy is a spermatocyte-specific gene. Since mTEAD-2 and mSgy were not expressed in the same cells, the mSgy/mTEAD-2 locus provides a unique paradigm for differential regulation of gene expression during mammalian development.
TEA domain (TEAD) proteins are highly conserved transcription factors involved in embryonic development and differentiation of various tissues. More recently, emerging evidences for a contribution of these proteins towards apoptosis and cell proliferation regulation have also been proposed. These effects appear to be mediated by the interaction between TEAD and its co-activator Yes-Associated Protein (YAP), the downstream effector of the Hippo tumour suppressor pathway.
We further investigated the mechanisms underlying TEAD-mediated apoptosis regulation and showed that overexpression or RNAi-mediated silencing of the TEAD1 protein is sufficient to protect mammalian cell lines from induced apoptosis, suggesting a proapoptotic function for TEAD1 and a non physiological cytoprotective effect for overexpressed TEAD1. Moreover we show that the apoptotic resistance conferred by altered TEAD1 expression is mediated by the transcriptional up-regulation of Livin, a member of the Inhibitor of Apoptosis Protein (IAP) family. In addition, we show that overexpression of a repressive form of TEAD1 can induce Livin up-regulation, indicating that the effect of TEAD1 on Livin expression is indirect and favoring a model in which TEAD1 activates a repressor of Livin by interacting with a limiting cofactor that gets titrated upon TEAD1 up-regulation. Interestingly, we show that overexpression of a mutated form of TEAD1 (Y421H) implicated in Sveinsson's chorioretinal atrophy that strongly reduces its interaction with YAP as well as its activation, can induce Livin expression and protect cells from induced apoptosis, suggesting that YAP is not the cofactor involved in this process.
Taken together our data reveal a new, Livin-dependent, apoptotic role for TEAD1 in mammals and provide mechanistic insight downstream of TEAD1 deregulation in cancers.
Interactions of leptin and leptin receptors play crucial roles during animal development and regulation of appetite and energy balance. In this study we analyzed expression pattern of a zebrafish leptin receptor gene in both developing and adult zebrafish using in situ hybridization and Q-PCR methods. Zebrafish leptin receptor message (lepr) was detected in all embryonic and larval stages examined, and in adult zebrafish. In embryonic zebrafish, lepr was mainly expressed in the notochord. As development proceeded, lepr expression in the notochord decreased, while its expression in several other tissues, including the trunk muscles and gut, became evident. In both larval and adult brains, large lepr expressing cells were detected in similar regions of the hindbrain. In adult zebrafish, lepr expression was also observed in several other brain regions including the hypothalamic lateral tuberal nucleus, the fish homolog of the arcuate nucleus. Q-PCR experiments confirmed lepr expression in the adult fish brain, and also showed lepr expression in several adult tissues including liver, muscle and gonads. Our results showed that lepr expression was both spatially and temporally regulated.
obese gene; brain; notochord; muscle; leptin; zebrafish; leptin receptor; in situ hybridization