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dpl-1 DP and efl-1 E2F act with lin-35 Rb to antagonize Ras signaling in C. elegans vulval development
1Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Abstract:
The synthetic multivulva (synMuv) genes define two functionally redundant pathways that antagonize RTK/Ras signaling during Caenorhabditis elegans vulval induction. The synMuv gene lin-35 encodes a protein similar to the mammalian tumor suppressor pRB and has been proposed to act as a transcriptional repressor. Studies using mammalian cells have shown that pRB can prevent cell cycle progression by inhibiting DP/E2F-mediated transcriptional activation. We identified C. elegans genes that encode proteins similar to DP or E2F. Loss-of-function mutations in two of these genes, dpl-1 DP and efl-1 E2F, caused the same vulval abnormalities as do lin-35 Rb loss-of-function mutations. We propose that rather than being inhibited by lin-35 Rb, dpl-1 DP and efl-1 E2F act with lin-35 Rb in transcriptional repression to antagonize RTK/Ras signaling during vulval development.
Insights
Synthetic multivulva (synMuv) genes regulate vulval development in C. elegans. This study reveals that dpl-1 DP and efl-1 E2F proteins function with lin-35 Rb in transcriptional repression, antagonizing RTK/Ras signaling.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Synthetic multivulva (synMuv) genes in C. elegans antagonize RTK/Ras signaling via two redundant pathways.
- The synMuv gene lin-35 encodes a pRB-like protein, proposed to function as a transcriptional repressor.
- Mammalian pRB inhibits DP/E2F-mediated transcription to prevent cell cycle progression.
Purpose of the Study:
- To investigate the roles of C. elegans DP and E2F homologs in vulval development.
- To elucidate the functional relationship between lin-35 Rb and its potential transcriptional partners dpl-1 DP and efl-1 E2F.
Main Methods:
- Identification of C. elegans DP and E2F homologs.
- Analysis of vulval development in loss-of-function mutants for dpl-1 and efl-1.
- Comparison of mutant phenotypes with lin-35 Rb loss-of-function mutations.
Main Results:
- Identified C. elegans genes encoding DP and E2F proteins.
- Loss-of-function mutations in dpl-1 DP and efl-1 E2F resulted in vulval abnormalities similar to lin-35 Rb mutations.
- These findings suggest a cooperative role in transcriptional repression.
Conclusions:
- dpl-1 DP and efl-1 E2F act with lin-35 Rb in a transcriptional repressor complex.
- This complex antagonizes RTK/Ras signaling during C. elegans vulval development.
- The mechanism involves dpl-1 DP and efl-1 E2F functioning with lin-35 Rb, rather than being inhibited by it.