Most Egg Calmodulin Is a Follicle Cell Contribution to the Cytoplasm of the Blattella germanica Oocyte

Developmental Biology

Joseph G. Kunkel¹  Yujun Zhang¹ 

[1]Biology Department, University of Massachusetts, Amherst, Massachusetts 01003

DOI  :  10.1006/dbio.1994.1049

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Ahighconcentrationofcalmodulin(CaM)appearsinmid-tolatevitellogeniccockroachfollicleswhichcomposes1.5%oftotalprotein.CaMlevelsduringoogenesiswereestimatedbydensitometricanalysisofimmunoblotsusinganti-BlattellagermanicaeggCaMantibodyasaprobe.CaMaccumulatesinthefolliclethroughouttheyolkdepositionphasemaintainingitshighestlevelofaccumulationduringthelater6-foldincreaseinoocytevolume.EvidencesuggeststhatthislateraccumulatedCaMissynthesizedbythefolliclecellsanddepositedintheoocyte.Invitroexperimentswith[35S]-metshowedthatthehighlyabundantCaMaccumulatinginvitellogenicfolliclesmaynotallbesynthesizedbytheoocyte.Isolatedfolliclecellsincorporate13-foldmore[35S]-metintoCaMthantheoocytesthemselvesbutdonotaccumulatetheproduct.ThefolliclecellsarecapableofproducingalltheCaMobservedinnewlyovulatedeggs.NoCaMisdetectableintransitinthehemolymphofthefemale.ThesefactsarguethatCaMproducedbyfolliclecellsisthemostlikelysourceofCaMinthevitellogenicoocyte.Indirectimmunofluorescentstainingwithanti-eggCaMdemonstratedthatinearly-andmidvitellogenicfolliclesCaMislocalizedinthecytoplasmoffolliclecellsandthecytoplasmiccompartmentsurroundingyolkgranulesofoocytesbutisexcludedfromyolkgranules.Immunofluorescencewasmostintenseinthecortexoftheoocyteandoutsidethemembranesofyolkgranules.TransportofCaMintothecytoplasmiccompartmentoftheoocyteispossiblewithoutinvokingtraditionaladsorptiveendocytosis.

【 授权许可】

Unknown