Cell surface glycosyltransferase activities during normal and mutant (TT) mesenchyme migration☆

[摘要] Migratingcellspossesssurfaceglycosyltransferaseactivitytowardextracellularsubstrates,andtheappearanceofenzymeactivitycoincideswiththeonsetofcellularmigration(B.D.Shur,1977a,b,Develop.Biol.58,23–39,40–55;E.A.TurleyandS.Roth,1979,Cell17,109–115).Inthispaper,surfaceglycosyltransferaseswereexaminedduringnormalandTTmutantmesenchymemigration.Ofsixglycosyltransferasesthatwereassayed,onlygalactosyltransferasewaspresentatsignificantlevelsonthecellsurface,despitethepresenceofavarietyofintracellularglycosyltransferases.Allcontrolshavebeenperformedtoshowclearlytheenzymeactivitywascellsurfacelocalized.InbothnormalandTTembryos,surfacegalactosyltransferaseactivitywaslocalized,byautoradiography,primarilytomigratingmesenchymalcells,andtoalesserdegree,topresumptiveneuralepithelium.Duringprimitivestreakformation,putativeTTembryosweredevoidofsurfacegalactosyltransferaseactivity.However,asdevelopmentprogressed,theTTlevelofactivityeventuallyexceededwild-typelevelsbytwo-tosixfoldandwasevidentinTTtissuespriortotheonsetofmicroscopicpathology.OthersurfaceenzymesassayeddidnotshowanyTT-dependentincreaseinactivity.Theextracellulargalactosylacceptorswerenotchloroform:methanolsoluble,andglycopeptidespreparedbyexhaustivePronasedigestionwereexcludedfromSephadexG-50.Thislargegalactosylatedglycoconjugatewasreadilydigestablewithendo-β-galactosidase,and,therefore,issimilartothepoly-N-acetyllactosaminechainspreviouslyidentifiedonearlyembryonictissues(A.Kapadia,T.Feizi,andM.J.Evans,1981,Exp.Cell.Res.131,185–195;T.Muramatsu,G.Gachelin,M.Damonneville,C.Delarbre,andF.Jacob,1979,Cell18,183–191;A.Heifetz,W.J.Lennarz,B.Libbus,andY.-C.Hsu,1980,Develop.Biol.80,398–408).Theseresultssupportaninvolvementofsurfacegalactosyltransferasesinmesenchymeformationandduringmigrationonpoly-N-acetyllactosaminesubstrates.

[学科分类] 生物科学（综合）