Genetic analysis of temperature-sensitive embryogenesis mutants in Caenorhabditis elegans

[摘要] Alargesetoftemperature-sensitive(ts)embryonicarrestmutantsinthenematodeCaenorhabditiseleganshasbeenisolated.Followingethylmethanesulfonatemutagenesis,tsmutantswereidentifiedfrom10,000segregatedclonesbyreplicaplatingfrom16to25°C.Atleast54independenttsdevelopmentalmutantsshowedembryonicarrestwhentheappropriatedevelopmentalstagewasshiftedup.Theserepresent28%oftheindependentdevelopmentalmutantsfrom294tsclonesfrom155mutagenizedanimals.Initialcharacterizationofthissubsetofembmutantsisreported.Mostofthemarrestinmiddleorlateembryogenesiswithabnormalterminalphenotypes.Additionalnonembryonicarreststages(dependingonshift-upregimen)suggestthatmanyembgenesarealsorequiredforpre-orpostembryonicdevelopment.Formostoftheembmutantsparentalgeneexpressionissufficientforembryonicdevelopmentat25°C.Basedoncomplementationanalysisof37newembmutantstogetherwith32isolatedbyotherinvestigators,25newembgenesarereported.ThisbringsthetotalofembryonicarrestgenesdefinedinC.elegansto54.Thenewgeneshavebeenmappedapproximately.Inthepresentset,10embgenesmapinthemiddleoflinkagegroupIII.Thefrequencyofoccurrenceofsecondallelesgivesoneestimate(byPoissonanalysis)forthenumberofgenesrequiredforembryogenesisofabout200.Asecondestimateisobtainedfromthefractionof28%embmutantsamongalltslethalmutantsinthescreen;foranestimated2000essentialgenesinC.elegans,thiscorrespondsto560genesrequiredforembryogenesis.Asmallsubsetofhighlymutablegenesisalsodescribed.Resultsofthepresentscreenforembmutantsarecomparedtothoseofothers.Severaltsmutantsgavecomplexlinkageresults(apparentlynotduetodoublemutations),suggestingchromosomerearrangements.

[学科分类] 生物科学（综合）