Regional differences in the developing foreleg of Drosophila melanogaster☆
[摘要] WetransplantedimaginaldisksofDrosophilamelanogasterfromlarvaeofthesecondhalfofthethirdlarvalinstarintoprepupae.Disksfromtheyoungestdonorsdifferentiatedbristlesofonlythedistalsegmentsoftheleg.Thesedisksalsoproducedunusuallylargeareasofcuticlethathadnobristles.Disksfromolderdonorsdifferentiatedbristlesofmoreproximalsegmentsandtheareaofcuticlewithnobristleswasreduced.Toaccountfortheregionalvariationintheseresults,theremustberegionaldifferencesamongtheprospectivelegcellsatsometimeduringtheperiodfromthesecondhalfofthethirdlarvalinstartotheendofadultbristledifferentiation.Weaskedwhetherprospectivedistalcellsweremoreadvancedthanprospectiveproximalcellsduringbristledifferentiation.Weestimatedwhenbristleprecursorcellsundergotheirfinalcelldivisionsbyheavilyirradiatingprepupaeandpupae.Weassumedthatcellsthatwereinsensitivetotheradiationhadcompletedtheircelldivisions.Thedistalsegmentswerethefirsttohaveinsensitivebristles.Mostlegbristlesbecameinsensitivebetween12and18hrafterpupariation.Thetarsushadalargerproportionofitsbristlesinsensitivethanthefemurat15hrafterpupariation.Wealsoinvestigatedwhenbristle-formingcellsbeginelongatingtheirbristleshafts.Weusedthelengthofbristlerudimentsasanindicatorofwhenelongationisinitiated.At35hrafterpupariation,bristlerudimentsofdistalsegmentsweretwotothreetimeslongerthanbristlerudimentsofproximalsegments.Wediscusshowtheseintersegmentaldifferencesobservedduringbristledifferentiationcanaccountfortheregionalvariationinresponseofdiscstransplantedintoolderhosts.However,wedonotexcludethepossibilitythatregionaldifferencesamongcellsofthelegtissueexistatstagesearlierthanthetimeofbristledifferentiation.
[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]
