RRC ID 48794
Author Ataeian M, Tegha-Dunghu J, Curtis DG, Sykes EM, Nozohourmehrabad A, Bajaj M, Cheung K, Srayko M.
Title Maternal MEMI Promotes Female Meiosis II in Response to Fertilization in Caenorhabditis elegans.
Journal Genetics
Abstract In most animals, female meiosis completes only after fertilization. Sperm entry has been implicated in providing a signal for the initiation of the final meiotic processes; however, a maternal component required for this process has not been previously identified. We report the characterization of a novel family of three highly similar paralogs (memi-1, memi-2, memi-3) that encode oocyte-specific proteins. A hyper-morphic mutation memi-1(sb41) results in failure to exit female meiosis II properly; however, loss of all three paralogs results in a "skipped meiosis II" phenotype. Mutations that prevent fertilization, such as fer-1(hc1), also cause a skipped meiosis II phenotype, suggesting that the MEMI proteins represent a maternal component of a postfertilization signal that specifies the meiosis II program. MEMI proteins are degraded before mitosis and sensitive to ZYG-11, a substrate-specific adapter for cullin-based ubiquitin ligase activity, and the memi-1(sb41) mutation results in inappropriate persistence of the MEMI-1 protein into mitosis. Using an RNAi screen for suppressors of memi-1(sb41), we identified a sperm-specific PP1 phosphatase, GSP-3/4, as a putative sperm component of the MEMI pathway. We also found that MEMI and GSP-3/4 proteins can physically interact via co-immunoprecipitation. These results suggest that sperm-specific PP1 and maternal MEMI proteins act in the same pathway after fertilization to facilitate proper meiosis II and the transition into embryonic mitosis.
Volume 204(4)
Pages 1461-1477
Published 2016-12-1
DOI 10.1534/genetics.116.192997
PII genetics.116.192997
PMID 27729423
PMC PMC5161279
MeSH Animals Caenorhabditis elegans / genetics* Caenorhabditis elegans / physiology Caenorhabditis elegans Proteins / genetics* Caenorhabditis elegans Proteins / metabolism Cell Cycle Proteins / genetics* Cell Cycle Proteins / metabolism Female Fertilization / genetics* Male Meiosis / genetics* Membrane Proteins / genetics Membrane Proteins / metabolism Mutation Oocytes / cytology Oocytes / metabolism* Protein Binding Proteolysis
IF 4.015
Times Cited 2
C.elegans tm3099 tm2638 tm3158