Caulobacter crescentus pili: Analysis of production during development☆
[摘要] ThepiliofCaulobactercrescentusarestructureswhoseappearanceisregulatedduringthedevelopmentoftheswarmercellpole.Piliareassembledduringthepredivisionalandswarmercellstages,atthesametimeastheflagellum,anddisappearastheswarmercelldifferentiatesintoastalkedcell.Pilinistheproteinwhichpolymerizestoformthepilus.Animmuneprecipitationassay,developedtoexaminetheperiodicityofpilinsynthesisduringthecellcycle,demonstratedthatpilinsynthesisbeginsintheearlystalkedcellandisprobablycompletedbeforecelldivision.Thus,theentireperiodofsynthesisoccursbeforethepiliareclearlyvisibleatthedifferentiatedcellpole.Likewise,thefunctionalstabilityofthepilinmRNAisrelativelyshort,furthersuggestingthattheproteinmonomersaccumulatepriortoassembly.Unlikethecaseoftheflagellins,experimentswiththeDNAreplicationinhibitorhydroxyureadidnotestablishacorrelationbetweentheDNAreplicationandtheonsetofpilinsynthesis.Inadditiontopilin,severalotherdevelopmentallyregulatedproteins,includingtheflagellins,arereproduciblyprecipitatedinthepilinimmunoassay.Theirpresenceintheprecipitateisaspecificconsequenceoftheantipilinantibody.Analysisoftheantibodypreparationsyieldedconflictingresults;electronmicroscopicstudieswithferritin-coupledantibodyanddoublediffusionanalysisindicatednobindingactivitytoanycellcomponentsotherthanpilin.However,anassaybasedonfiltertransferredpreparationsofelectrophoresedcellproteinsindicatedthatatleastoneadditionalclassofproteinsintheimmuneprecipitatemaybindpilinantibody.TheseresultsarediscussedinthecontextofthepossibleformationofadiscretemembranecomplexinthepolarregionofthecellwhichmaybeinvolvedintheregulationofspatialdevelopmentinCaulobacter.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
