Chromosome-biased binding and gene regulation by the C. elegans DRM complex
Ontology highlight
ABSTRACT:
ORGANISM(S): Caenorhabditis elegans
SUBMITTER: Kirsten Hagstrom
PROVIDER: E-GEOD-28853 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:DRM is a conserved transcription factor complex that includes E2F/DP and pRB family proteins and plays important roles in development and cancer. Here we analyze genome-wide binding and function of the C. elegans DRM subunit LIN-54. We demonstrate that LIN-54 DNA-binding activity is required for the DRM complex to efficiently bind and regulate target genes containing adjacent putative E2F/DP and LIN-54 binding sites. We show that LIN-54 binds to the promoters of genes involved in cell division, development, and reproduction, and acts differently in the germline versus the soma. The E2F/DP-LIN-54 binding motif, individual target genes, and overall DRM function are conserved among worms, flies, and humans. Despite this conservation, we discovered one striking feature of C. elegans DRM not shared in flies or humans: it is depleted from X chromosomes. We show that DRM binding, the E2F-LIN-54 hybrid motif, and LIN-54-regulated genes are all autosome-enriched. Chromatin-immunoprecipitation of mixed staged wild-type C.elegans (N2, Bristol strain) was performed using non-commercial anti-LIN-54 antibody raised in guinea pig (Harrison et at. 2006).
2011-04-27 | E-GEOD-28852 | biostudies-arrayexpress
Project description:DRM is a conserved transcription factor complex that includes E2F/DP and pRB family proteins and plays important roles in development and cancer. Here we perform microarray expression profiling analysis of lin-54, a DNA-binding member of the DRM complex. To identify genes regulated by LIN-54 in soma and germline, we analyzed wild-type and lin-54 mutant C. elegans embryos and isolated germlines. We chose embryos because they consist primarily of somatic cells, at a developmental stage with both active cell divisions and dynamic developmental gene expression programs. Since lin-54 null animals are sterile, embryos were obtained from a strain carrying the partial loss-of-function allele lin-54(n2990). Germlines were dissected from lin-54(n3423) null adults that lack detectable transcript and protein. The results revealed conserved roles for DRM in regulating genes involved in cell division, development, and reproduction. We find LIN-54 promotes expression of reproduction genes in the germline, but prevents ectopic activation of germline-specific genes in embryonic soma. Strikingly, genomics and cytological analyses show that DRM binding, a DRM binding motif, and LIN-54-regulated genes are all autosome-enriched. One paradoxical exception occurs the germline, where DRM binds autosomes but genes down-regulated in DRM mutants are enriched on X chromosomes. We compared embryonic or germline gene expression profile of lin-54 mutants with that of wild-type N2 C. elegans. Embryos were obtained from a strain carrying the partial loss-of-function allele lin-54(n2990) grown at 25C for one generation. Germlines were isolated from lin-54(n3423) null adults that lack detectable lin-54 transcript and protein. We isolated the germline region from the tip until late pachytene stage of meiosis, because nuclei in this region are morphologically similar between wild-type and mutant and are all undergoing X chromosome silencing. 3 biological replicates of each genotype/tissue were examined.
2011-04-09 | E-GEOD-28494 | biostudies-arrayexpress
Project description:Here we uncover antagonistic regulation of transcript levels in the germline of Caenorhabditis elegans hermaphrodites. The histone methyltransferase MES-4 marks genes expressed in the germline with methylated Lys36 on histone H3 (H3K36me) and promotes their transcription; MES-4 also represses genes normally expressed in somatic cells and genes on the X chromosomes. The DRM complex, which includes E2F/DP and Retinoblastoma homologs, affects germline gene expression and prevents excessive repression of X-chromosome genes. Using genome-scale analyses of germline tissue, we show that common germline-expressed genes are activated by MES-4 and repressed by DRM, and that MES-4 and DRM co-bind many germline-expressed genes. Reciprocally, MES-4 represses and DRM activates a set of autosomal soma-expressed genes and overall X-chromosome gene expression. Mutations in mes-4 or the DRM subunit lin-54 oppositely skew target transcript levels and cause sterility; a double mutant restores near wild-type transcript levels and germ cell development. Together, 'yin-yang' regulation by MES-4 and DRM ensures transcript levels appropriate for germ cell function, elicits robust but not excessive dampening of X-chromosome-wide transcription, and may poise genes for future expression changes. Our study reveals that conserved transcriptional regulators implicated in development and cancer counteract each other to fine-tune transcript dosage. We compared germline gene expression profile of wild-type N2 C. elegans, lin-54(n3423) M+Z- mutant, mes-4(ok2326) M+Z- mutant, and lin-54(n3423);mes-4(ok2326) M+Z-mutant grown at 20C. 50~70 Germlines were dissected from young adults (24hours after L4 stage), and region from the tip until late pachytene stage of meiosis were collected. Three biological replicates for each strain were performed.
2013-11-05 | E-GEOD-52064 | biostudies-arrayexpress
Project description:Initiation of DNA replication requires binding of the initiator protein, DnaA, to specific binding sites in the chromosomal origin of replication, oriC. In low G+C Gram-positive bacteria, the primosomal proteins DnaD and DnaB, in conjunction with loader ATPase DnaI, load the replicative helicase at oriC, and this depends on DnaA. DnaD and DnaB are also required to load the replicative helicase outside of oriC during replication restart, in a DnaA-independent manner. DnaA also binds to many sites around the chromosome, outside of oriC, and acts as a transcription factor at several of these. Using chromatin immunoprecipitation, we found that DnaD and DnaB, but not the replicative helicase, are associated with many of the chromosomal regions bound by DnaA in vivo in Bacillus subtilis. This association was dependent on DnaA and the order of recruitment was the same as that at oriC, but was independent of a functional oriC. The presence of DnaD and DnaB at the secondary (non-oriC) targets of DnaA in the absence of helicase loading indicates a possible role for DnaD and DnaB in modulating the activity of DnaA. The genome-wide binding profiles of DnaA, DnaD, DnaB and DnaC were determined. Binding profiles were determined in exponentially growing cells with and without HPUra treatment. Three biological replicates were analyzed per protein/treatment (one per array). Enrichment in immunoprecipitated samples versus total genomic DNA were determined.
2010-12-07 | E-GEOD-23686 | biostudies-arrayexpress
Project description:MicroRNAs are regulators of gene expression whose functions are critical for normal development and physiology. We have previously characterized mutations in a Caenorhabditis elegans microRNA-specific Argonaute ALG-1 (Argonaute-like gene) that are antimorphic [alg-1(anti)]. alg-1(anti) mutants have dramatically stronger microRNA-related phenotypes than animals with a complete loss of ALG-1. ALG-1(anti) miRISC (microRNA induced silencing complex) fails to undergo a functional transition from microRNA processing to target repression. To better understand this transition, we characterized the small RNA population associated with ALG-1(anti) complexes in vivo. alg-1(anti) mutants dramatically overaccumulated microRNA* (passenger) strands, and immunoprecipitated ALG-1(anti) complexes contained nonstoichiometric yields of mature microRNA and microRNA* strands, with some microRNA* strands present in the ALG-1(anti) Argonaute far in excess of the corresponding mature microRNAs. We show complex and microRNA-specific defects in microRNA strand selection and microRNA* strand disposal. For certain microRNAs (for example mir-58), microRNA guide strand selection by ALG-1(anti) appeared normal, but microRNA* strand release was inefficient. For other microRNAs (such as mir-2), both the microRNA and microRNA* strands were selected as guide by ALG-1(anti), indicating a defect in normal specificity of the strand choice. Our results suggest that wild-type ALG-1 complexes recognize structural features of particular microRNAs in the context of conducting the strand selection and microRNA* ejection steps of miRISC maturation. Deep-sequencing was performed on cDNA libraries made from total RNA and RNA immunoprecipitated with ALG-1 from mixed-staged populations of three strains: three biological replicates from wild-type animals and two biological replicates each from alg-1(ma192) and alg-1(ma202) mutant animals. In addition, deep-sequencing was performed on cDNA libraries made from L2-staged total RNA in two biological replicates from wildtype and alg-1(ma202) animals and one biological replicate of alg-1(ma192).
2015-09-07 | E-GEOD-72659 | biostudies-arrayexpress
Project description:DRM is a conserved transcription factor complex that includes E2F/DP and pRB family proteins and plays important roles in development and cancer. Here we analyze genome-wide binding and function of the C. elegans DRM subunit LIN-54. We demonstrate that LIN-54 DNA-binding activity is required for the DRM complex to efficiently bind and regulate target genes containing adjacent putative E2F/DP and LIN-54 binding sites. We show that LIN-54 binds to the promoters of genes involved in cell division, development, and reproduction, and acts differently in the germline versus the soma. The E2F/DP-LIN-54 binding motif, individual target genes, and overall DRM function are conserved among worms, flies, and humans. Despite this conservation, we discovered one striking feature of C. elegans DRM not shared in flies or humans: it is depleted from X chromosomes. We show that DRM binding, the E2F-LIN-54 hybrid motif, and LIN-54-regulated genes are all autosome-enriched.
2011-04-27 | GSE28852 | GEO
Project description:DRM is a conserved transcription factor complex that includes E2F/DP and pRB family proteins and plays important roles in development and cancer. Here we perform microarray expression profiling analysis of lin-54, a DNA-binding member of the DRM complex. To identify genes regulated by LIN-54 in soma and germline, we analyzed wild-type and lin-54 mutant C. elegans embryos and isolated germlines. We chose embryos because they consist primarily of somatic cells, at a developmental stage with both active cell divisions and dynamic developmental gene expression programs. Since lin-54 null animals are sterile, embryos were obtained from a strain carrying the partial loss-of-function allele lin-54(n2990). Germlines were dissected from lin-54(n3423) null adults that lack detectable transcript and protein. The results revealed conserved roles for DRM in regulating genes involved in cell division, development, and reproduction. We find LIN-54 promotes expression of reproduction genes in the germline, but prevents ectopic activation of germline-specific genes in embryonic soma. Strikingly, genomics and cytological analyses show that DRM binding, a DRM binding motif, and LIN-54-regulated genes are all autosome-enriched. One paradoxical exception occurs the germline, where DRM binds autosomes but genes down-regulated in DRM mutants are enriched on X chromosomes.
2011-04-09 | GSE28494 | GEO
Project description:Oct4 stemness gene encoding a transcription factor has been shown to overexpress in cancers. However, precise mechanisms of Oct4 relevant to transcriptional reprogramming leading to somatic cancer progression remain unclear. To address the Oct4-mediated transcriptional program in lung cancer, we integrated genome-wide Oct4 binding profiles from chromatin-immunoprecipitation sequencing and ENCODE datasets. We identified that Oct4 occupied at functional promoter and enhancer regions of genes which play key roles in several signaling pathways involving tumorigenesis. Genome-wide Oct4 binding sites were identified via chromatin immunoprecipitation-sequencing analysis of vecoter control and stably Oct4-overexpressing A549 lung cancer cells. ChIP-seq analyses were performed in duplicated samples using Applied Biosystems SOLiD system.
2015-02-04 | E-GEOD-58462 | biostudies-arrayexpress
Project description:The elongation stage of transcription is a highly regulated in metazoan. We previously purified the AFF1/AFF4-containing Super Elongation Complex (SEC) as a major regulator of development and cancer pathogenesis. Here, we report the biochemical isolation of SEC-like 2 (SEC-L2) and SEC-like 3 (SEC-L3) containing AFF2 and AFF3 in association with P-TEFb, ENL, and AF9. The SEC family members demonstrate high levels of Pol II CTD kinase activity, however, only SEC is required for the proper induction of the HSP70 gene upon stress. Genome-wide mRNA-seq analyses demonstrate that SEC-L2-3 control the expression of different subsets of genes, while AFF4/SEC plays a more dominant role in rapid gene expression in cells. MYC is one of the direct targets of AFF4/SEC, and the SEC requirement to the MYC gene regulates its expression in different cancer cells bearing either acute myeloid or lymphoid leukemia. These findings suggest that AFF4/SEC could be a potential therapeutic target for the treatment of leukemia or other cancers associated with MYC overexpression. RNA-seq in human embyonic kidney 293T cells of wild-type and after RNAi of AFF2, AFF3, AFF4. ChIP-seq of AFF4 and Pol2 in human 293T cells.
2012-05-01 | E-GEOD-34097 | biostudies-arrayexpress
Project description:CCAAT/enhancer binding protein beta (C/EBPb) is a member of a family of highly conserved transcription factors that regulates numerous genes involved in proliferation and differentiation in a variety of tissues. C/EBPb is deregulated in human breast cancer and germline deletion of this gene results in multiple defects in mammary gland development. We hypothesized that C/EBPb regulates mammary stem cell self-renewal, maintenance and/or differentiation through the regulation of multiple target genes that coordinate mammary gland development. Utilizing both a germline knockout mouse model and a conditional knockout strategy, we demonstrated that mammosphere formation was significantly decreased in C/EBPb-deficient mammary epithelial cells (MECs). The ability of C/EBPb-deleted MECs to regenerate the mammary gland in vivo was severely impaired when transplanted at limiting dilution. Furthermore, serial transplantation of C/EBPb-null mammary tissue resulted in decreased outgrowth potential when compared to wildtype, and an early senescence phenotype. Flow cytometric analysis revealed that C/EBPb-null MECs contain a lower frequency of repopulating stem cells accompanied by an increase in committed, differentiated luminal cells as compared to wildtype. Microarray analysis of stem/progenitor cell populations was performed and revealed an alteration in cell fate specification in C/EBPb-null glands, exemplified by the aberrant expression of basal markers in the luminal cell compartment. Collectively, our studies demonstrate that C/EBPb is a critical regulator of mammary stem cell differentiation, and an important determinant of luminal cell fate specification. Experiment Overall Design: To identify potential signaling pathways regulated by C/EBPb in stem/progenitor cells, microarray analysis was performed on two stem/progenitor cell subpopulations. For this analysis, subpopulations defined by LIN-CD24+CD29hi and LIN-CD24hiCD29lo were FACS sorted from wildtype and germline C/EBPb-/- glands, and RNA was isolated from each group.
2010-02-05 | E-GEOD-16380 | biostudies-arrayexpress