Analysis of actin synthesis in early sea urchin development☆

[摘要] Earlierstudieshaveshownthatwhileactinrepresentsoneofthemostabundantproteinsintheseaurchinegg,actinmRNAlevelsandsynthesisarerelativelylowintheembryountilapproximately8hrafterfertilization.Atthistime,mRNAabundanceandproteinsynthesisbegintoriseandby18hrtheamountofactinmRNAhasincreased10-to25-fold.Inthisstudy,wehaveexaminedshiftsinthesynthesisofactinisoformsbytwo-dimensionalgelelectrophoresisandwehaverelatedtheseshiftstoknownchangesinembryonicactinmRNAs.InvivolabelingofproteinsorinvitrotranslationofRNAisolatedfromvariousdevelopmentalstagesshowsanincreaseindenovoactinsynthesiswhichcorrespondstotheincreasesinactinmRNA.Thepredominantformofactinstoredintheeggcomigrateswithmammalianβ-actinandrepresentsthemajorspeciessynthesizedatallstagesexamined.Twootheractinvariantsmigratetotheacidicandbasicsideoftheβ-actin-likespecies,butdonotcomigratewithmammalianα-andγ-actinmarkers.Atblastula,theseactinspotsarepresentintheapproximateratiosof1:10:2(acidic:β-like:basic).Themorebasicvariantappearstorepresentanunacetlyatedprecursorofthepredominantisoformandtheacidicvariantmayalsorepresentamodifiedderivative.Thesestudies,comparingtheappearanceofproteinvariantswiththeappearanceofspecificactingenetranscripts,areconsistentwiththemodelthatseveralexpressedgenesallencodethepredominantisoform.

[学科分类] 生物科学（综合）