The Major Subacrosomal Occupant of Bull Spermatozoa Is a Novel Histone H2B Variant Associated with the Forming Acrosome during Spermiogenesis

Developmental Biology

Ritu B. Aul¹  Richard J. Oko¹ 

[1] Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada, K7L 3N6

关键词: spermatozoa;    perinuclear theca;    spermiogenesis;    acrosome development;    histone;    H2B;    bipartite nuclear targeting sequence;   

DOI  :  10.1006/dbio.2001.0427

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Recentstudiesonthestructuralcompositionofmammalianspermheadshaveshownacongregateofunidentifiedproteinsoccupyingtheperipheryofthemammalianspermnucleus,formingalayerofcondensedcytosol.Theseproteinsaretheperinucleartheca(PT)andcanbecategorizedintoSDS-solubleandSDS-insolublecomponents.ThepresentstudyfocusedonidentifyingthemajorSDS-insolublePTprotein,whichwelocalizedtothesubacrosomallayerofbovinespermatozoaandclonedbyimmunoscreeningabulltesticularcDNAlibrary.Theisolatedclonesencodeaproteinof122aminoacidsthatbears67%similaritywithhistoneH2Bandcontainsapredictedhistonefoldmotif.Thenovelaminoterminusoftheproteincontainsapotentialbipartitenucleartargetingsequence.Hence,weidentifiedthisprominentsubacrosomalcomponentasanovelH2Bvariant,SubH2Bv.NorthernblotanalysesofSubH2BvmRNAexpressionshowedthatitistestis-specificandisalsopresentinmuridtestes.ImmunocytochemicalanalysisshowedSubH2Bvintimatelyassociates,temporallyandspatially,withacrosomeformation.WhilethemolecularfeaturesofSubH2Bvarecommontonuclearproteins,itisneverseendevelopmentallywithinthenucleusofthespermatid.Consideringitsdevelopmentalandmolecularcharacteristics,wehavepostulatedrolesofSubH2Bvinacrosomeassemblyandacrosome-nucleardocking.

【 授权许可】

Unknown