Promotion of oogenesis and embryogenesis in the C. elegans gonad by EFL-1/DPL-1 (E2F) does not require LIN-35 (pRB).
In Caenorhabditis elegans, EFL-1 (E2F), DPL-1 (DP) and LIN-35 (pRb) act coordinately in somatic tissues to inhibit ectopic cell division, probably by repressing the expression of target genes. EFL-1, DPL-1 and LIN-35 are also present in the germline, but do not always act together. Strong loss-of-function mutations in either efl-1 or dpl-1 cause defects in oogenesis that result in sterility, while lin-35 mutants are fertile with reduced broods. 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 germline, and the genes that it acts on are for the most part distinct from those regulated by EFL-1 and/or DPL-1. Thus, in vivo, C. elegans E2F directly promotes oogenesis and embryogenesis through the activation of a tissue-specific transcriptional program that does not require LIN-35.
Chi
Woo
W
Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA.
Reinke
Valerie
V
D000818:Animals; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics / Q000254:growth & development*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D050684:E2F Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D047108:Embryonic Development / Q000235:genetics; D005298:Fertility / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006066:Gonads / Q000196:embryology / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D009866:Oogenesis / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000235:genetics; D011973:Receptors, LDL / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation
D029742:Caenorhabditis elegans Proteins; D050684:E2F Transcription Factors; C102175:MEX-3 protein, C elegans; C514538:RME-2 protein, C elegans; D016601:RNA-Binding Proteins; D011973:Receptors, LDL; D012097:Repressor Proteins; D014157:Transcription Factors; C433249:dpl-1 protein, C elegans; C493765:efl-1 protein, C elegans; C116485:lin-35 protein, C elegans