Project description:LIN-35 is the single C. elegans ortholog of the mammalian pocket protein family members, pRb, p107, and p130. To gain insight into the roles of pocket proteins during development, a microarray analysis was performed with lin-35 mutants. Stage-specific regulation patterns were revealed, indicating that LIN-35 plays diverse roles at distinct developmental stages. LIN-35 was found to repress the expression of many genes involved in cell proliferation in larvae, an activity that is carried out in conjunction with E2F. In addition, LIN-35 was found to regulate neuronal genes during embryogenesis and targets of the intestinal-specific GATA transcription factor, ELT-2, at multiple developmental stages. Additional findings suggest that LIN-35 functions in cell cycle regulation in embryos in a manner that is independent of E2F. A comparison of LIN-35-regulated genes with known fly and mammalian pocket-protein targets revealed a high degree of overlap, indicating strong conservation of pocket protein functions in diverse phyla. Based on microarray results and our refinement of the C. elegans E2F consensus sequence, we were able to generate a comprehensive list of putative E2F-regulated genes in C. elegans. These results implicate a large number of genes previously unconnected to cell cycle control as having potential roles in this process. Keywords: time course
Project description:LIN-35 is the single C. elegans ortholog of the mammalian pocket protein family members, pRb, p107, and p130. To gain insight into the roles of pocket proteins during development, a microarray analysis was performed with lin-35 mutants. Stage-specific regulation patterns were revealed, indicating that LIN-35 plays diverse roles at distinct developmental stages. LIN-35 was found to repress the expression of many genes involved in cell proliferation in larvae, an activity that is carried out in conjunction with E2F. In addition, LIN-35 was found to regulate neuronal genes during embryogenesis and targets of the intestinal-specific GATA transcription factor, ELT-2, at multiple developmental stages. Additional findings suggest that LIN-35 functions in cell cycle regulation in embryos in a manner that is independent of E2F. A comparison of LIN-35-regulated genes with known fly and mammalian pocket-protein targets revealed a high degree of overlap, indicating strong conservation of pocket protein functions in diverse phyla. Based on microarray results and our refinement of the C. elegans E2F consensus sequence, we were able to generate a comprehensive list of putative E2F-regulated genes in C. elegans. These results implicate a large number of genes previously unconnected to cell cycle control as having potential roles in this process. Experiment Overall Design: We compared transcriptom profiles of lin-35 mutants and control N2 worms at 3 developmental stages (embryonic, L1 and L4). Experiment Overall Design: Each comparison was done in triplicate on independently grown and isolated animals.
Project description:Microarray-based expression profiling of dissected gonads from efl-1, dpl-1 and lin-35 mutants reveals that EFL-1 and DPL-1 promote expression of an extensively overlapping set of target genes, consistent with the expectation that these two proteins function as a heterodimer. Regulatory regions upstream of many of these target genes have a canonical E2F binding site, suggesting that their regulation by EFL-1/DPL-1 is direct. Many EFL-1/DPL-1 responsive genes encode proteins required for oogenesis and early embryogenesis, rather than cell cycle components. By contrast, LIN-35 appears to function primarily as a repressor of gene expression in the germ line, and the genes that it acts on are for the most part distinct from those regulated by EFL-1 and/or DPL-1 Keywords: Mutant analysis of dpl-1, efl-1, and lin-35 in dissected C. elegans gonads
Project description:Microarray-based expression profiling of dissected gonads from efl-1, dpl-1 and lin-35 mutants reveals that EFL-1 and DPL-1 promote expression of an extensively overlapping set of target genes, consistent with the expectation that these two proteins function as a heterodimer. Regulatory regions upstream of many of these target genes have a canonical E2F binding site, suggesting that their regulation by EFL-1/DPL-1 is direct. Many EFL-1/DPL-1 responsive genes encode proteins required for oogenesis and early embryogenesis, rather than cell cycle components. By contrast, LIN-35 appears to function primarily as a repressor of gene expression in the germ line, and the genes that it acts on are for the most part distinct from those regulated by EFL-1 and/or DPL-1 We isolated dissected gonads from dpl-1, efl-1 and lin-35 mutant adults and compared each to control dissected gonads. RNA was linearly amplified prior to labeling for all genotypes. Each comparison was done in triplicate (dpl-1 and lin-35) or in quadruplicate (efl-1) on independently grown and isolated animals.
Project description:The highly conserved DREAM transcriptional repressor complex contains an RB-like pocket protein, an E2F-DP transcription factor heterodimer, and the 5-subunit MuvB complex. Using CRISPR/Cas9 targeted mutagenesis, we disrupted the interaction between the sole Caenorhabditis elegans pocket protein LIN-35 and the MuvB subunit LIN-52. A triple alanine substitution of LIN-52's LxCxE motif (3A) severed LIN-35-MuvB association and caused classical DREAM mutant phenotypes, including synthetic multiple vulvae, high-temperature arrest, and ectopic expression of germline genes in the soma. We performed RNA-seq in lin-52(3A) mutant late embryos (4 replicates) compared to lin-52(WT) wild-type late embryos (4 replicates) to assess the genome-wide effects on gene expression that result from severing LIN-35-MuvB association.
Project description:The Retinoblastoma-like pocket proteins p130 and p107 act as gatekeepers of the cell cycle through their activity within the DREAM (Dp/Rb-like/E2F/MuvB) transcriptional repressor complex. The goal of this study was to address how the pocket protein contributes to DREAM complex assembly and function on chromatin by utilizing a protein null mutant of the only C. elegans pocket protein LIN-35. We performed ChIP-seq of C. elegans DRM subunits in wild-type and lin-35 null late embryos to assess the effect on their chromatin localization following loss of LIN-35.
Project description:The mammalian Retinoblastoma (RB) family including pRB, p107, and p130 represses E2F target genes through mechanisms that are not fully understood. In D. melanogaster, RB-dependent repression is mediated in part by the multisubunit protein complex Drosophila RBF, E2F, and Myb (dREAM) that contains homologs of the C. elegans synthetic multivulva class B (synMuvB) gene products. Using an integrated approach combining proteomics, genomics, and bioinformatic analyses, we identified a p130 complex termed DP, RB-like, E2F, and MuvB (DREAM) that contains mammalian homologs of synMuvB proteins LIN-9, LIN-37, LIN-52, LIN-54, and LIN-53/RBBP4. DREAM bound to more than 800 human promoters in G0 and was required for repression of E2F target genes. In S phase, MuvB proteins dissociated from p130 and formed a distinct submodule that bound MYB. This work reveals an evolutionarily conserved multisubunit protein complex that contains p130 and E2F4, but not pRB, and mediates the repression of cell cycle-dependent genes in quiescence. Keywords: Gene expression analysis during cell cycle
Project description:The mammalian Retinoblastoma (RB) family including pRB, p107, and p130 represses E2F target genes through mechanisms that are not fully understood. In D. melanogaster, RB-dependent repression is mediated in part by the multisubunit protein complex Drosophila RBF, E2F, and Myb (dREAM) that contains homologs of the C. elegans synthetic multivulva class B (synMuvB) gene products. Using an integrated approach combining proteomics, genomics, and bioinformatic analyses, we identified a p130 complex termed DP, RB-like, E2F, and MuvB (DREAM) that contains mammalian homologs of synMuvB proteins LIN-9, LIN-37, LIN-52, LIN-54, and LIN-53/RBBP4. DREAM bound to more than 800 human promoters in G0 and was required for repression of E2F target genes. In S phase, MuvB proteins dissociated from p130 and formed a distinct submodule that bound MYB. This work reveals an evolutionarily conserved multisubunit protein complex that contains p130 and E2F4, but not pRB, and mediates the repression of cell cycle-dependent genes in quiescence. Experiment Overall Design: Gene expression during the cell cycle in T98G cells. Cells were serum starved for 72 hours to induce G0 and then restimuated to enter cell cycle by serum addition. BrdU and FACS was done simultaneously to confirm their cell cycle phase.
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.