An RNAi-Based Suppressor Screen Identifies Interactors of the Myt1 Ortholog of Caenorhabditis elegans

Oocyte maturation in all species is controlled by a protein complex termed the maturation promoting factor (MPF). MPF is comprised of a cyclin-dependent kinase (CDK) and its partner cyclin, and is regulated by dueling regulatory phosphorylation events on the CDK. In Caenorhabditis elegans, the Wee1/Myt1 ortholog WEE-1.3 provides the inhibitory phosphorylations on CDK-1 that keep MPF inactive and halts meiosis. Prior work has shown that depletion of WEE-1.3 in C. elegans results in precocious oocyte maturation in vivo and a highly penetrant infertility phenotype. This study sought to further define the precocious maturation phenotype and to identify novel interactors with WEE-1.3. We found that WEE-1.3 is expressed throughout the germline and in developing embryos in a perinuclear pattern, and demonstrated that oocytes in WEE-1.3-depleted germlines have begun to transcribe embryonic genes and exhibit inappropriate expression of proteins normally restricted to fertilized eggs. In addition, we performed an RNAi suppressor screen of the infertile phenotype to identify novel factors that, when co-depleted with WEE-1.3, restore fertility to these animals. We screened ~1900 essential genes by RNAi feeding and identified 44 (~2% of the tested genes) that are suppressors of the WEE-1.3 depletion phenotype. The suppressors include many previously unidentified players in the meiotic cell cycle, and represent a pool of potential WEE-1.3 interacting proteins that function during C. elegans oocyte maturation and zygotic development