CGC Bibliography Paper 5250

A lin-45 raf enhancer screen identifies eor-1, eor-2 and unusual alleles of Ras pathway genes in Caenorhabditis elegans.

Rocheleau CE, Howard RM, Goldman AP, Volk ML, Girard LJ, Sundaram MV

Medline:
12019228
Citation:
Genetics 161: 121-131 2002
Type:
ARTICLE
Genes:
eor-1 eor-2 gap-1 ksr-1 let-4 let-23 let-60 let-277 let-278 let-279 let-280 let-281 let-282 let-284 let-341 lin-1 lin-3 lin-25 lin-45 mek-2 mpk-1 sem-5 sur-2 sur-6 mDf7 mDf8
Abstract:
In Caenorhabditis elegans, the Ras/Raf/MEK/ERK signal transduction pathway controls multiple processes including excretory system development, P12 fate specification, and vulval cell fate specification. To identify positive regulators of Ras signaling, we conducted a genetic screen for mutations that enhance the excretory system and egg laying defects of hypomorphic lin-45 raf mutants. This screen identified unusual alleles of several known Ras pathway genes, including a mutation removing the second SH3 domain of the sem-5/Grb2 adaptor, a temperature-sensitive mutation in the helical hairpin of let-341/Sos, a gain-of-function mutation affecting a potential phosphorylation site of the lin-1 Ets domain transcription factor, a dominant-negative allele of ksr-1, and hypomorphic alleles of sur-6/PP2A-B, sur-2/Mediator, and lin-25. In addition, this screen identified multiple alleles of two newly identified genes, eor-1 and eor-2, that play a relatively weak role in vulval fate specification but positively regulate Ras signaling during excretory system development and P12 fate specification. The spectrum of identified mutations argues strongly for the specificity of the enhancer screen and for a close involvement of eor-1 and eor-2 in Ras signaling.