Identification of a region of mouse zona pellucida glycoprotein mZP3 that possesses sperm receptor activity

摘要

TheabilityofmousezonapellucidaglycoproteinZP3(mZP3)tofunctionasaspermreceptorisattributabletocertainofitsoligosaccharides,nottoitspolypeptide(P.M.Wassarman,1990.Development108,1a€“17).Here,purified,radioiodinatedmZP3wasdigestedbyeitherpapainorV8protease,andtheglycopeptidesproducedwerefractionatedbyHPLCandassayedforspermreceptoractivityinvitro.EachproteolyticdigestofmZP3containedaheavilyglycosylatedpeptide,a??55,000apparentMr,thatexhibitedspermreceptoractivityinvitro.TodeterminetheregionofmZP3polypeptidefromwhichtheactiveglycopeptideswerederived,Westerngelimmunoblotting,employinganantiserumdirectedagainstaspecificmZP3peptideepitope,andautomatedamino-terminalaminoacidsequencingwereemployed.ResultsoftheseexperimentsstronglysuggestthattheactiveglycopeptidesproducedbydigestionofmZP3witheitherpapainorV8proteasearederivedfromthesameregionofthecarboxy-terminalhalfofthemZP3polypeptide.TheseandotherfindingsarediscussedintermsofmZP3structureandfunction.