XGef is a CPEB-interacting protein involved in Xenopus oocyte maturation

摘要

XGefwasisolatedinascreenforproteinsinteractingwithCPEB,aregulatorofmRNAtranslationinearlyemXenopus/emdevelopment.XGefisaRho-familyguaninenucleotideexchangefactorandactivatesCdc42inmammaliancells.EndogenousXGef(58kDa)interactswithrecombinantCPEB,andrecombinantXGefinteractswithendogenousCPEBinemXenopus/emoocytes.InjectionofXGefantibodiesintostageVIemXenopus/emoocytesblocksprogesterone-inducedoocytematurationandpreventsthepolyadenylationandtranslationofc-emmos/emmRNA;injectionofXGefrescuestheseevents.OverexpressionofXGefinoocytesacceleratesprogesterone-inducedoocytematurationandthepolyadenylationandtranslationofc-emmos/emmRNA.OverexpressionofanucleotideexchangedeficientversionofXGef,whichretainstheabilitytointeractwithCPEB,nolongeracceleratesoocytematurationorMossynthesis,suggestingthatXGefexchangefactoractivityisrequiredfortheinfluenceofoverexpressedXGefonoocytematuration.XGefoverexpressioncontinuestoacceleratec-emmos/empolyadenylationintheabsenceofMosprotein,butdoesnotstimulateMAPKphosphorylation,MPFactivation,oroocytematuration,indicatingthatXGefmayfunctionthroughtheMospathwaytoinfluenceoocytematuration.TheseresultssuggestthatXGefmaybeanearlyactingcomponentoftheprogesterone-inducedoocytematurationpathway./p/div