Denervation effects on DNA replication and mitosis during the initiation of limb regeneration in adult newts☆
[摘要] Histologicalandcellulareventsduringthefirst2weeksafteramputationofadultnewtforelimbswerecomparedunderconditionsofinnervationanddenervationinordertoascertainthefirstnerve-dependentstepintheregenerationprocess.Formationofawoundepithelium,histolysis,anddedifferentiationoccurred,despitetheabsenceofnerves,inamannersimilartothatoftheregeneratinglimbs.Autoradiographyshowedthatcellsinthedenervatedlimb-stumpsincorporate[3H]thymidineintoDNAbeginningonday4andthatduringthefirstweekafteramputationtheselimbstumpsresembledthecontralateralcontrolsinoveralllabelingindices,inthedistributionofthelabelednuclei,andintensityoflabeling.MicrospectrophotometricdeterminationsofnuclearDNAcontentsinthededifferentiatedcellsofdenervatedandinnervatedlimbsrevealedthatinbothcasesreplicationoftheentirechromosomalcomplementoccurred.Celldivision,whichfirstbegan6daysafteramputation,andearlyblastemaformationwereobservedonlyintheinnervatedlimbstumps.Alikelyexplanationoftheseresults,consistentwiththepreponderanceoftheliteratureonregeneration,isthatlimbstumpscaninitiatetheregenerationprocessintheabsenceofnervesbutthatthecellsareblockedintheG2phaseofthefirstcellcycleandconsequentlydonotproliferatetoformablastema.
[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]
