【作者】 徐丽； 梁辉； 牛艳山； 王英； 司马杨虎； 徐世清；

【Author】 Li Xu,Hui Liang,Yanshan Niu,Ying Wang and Yanghu Sima,Shiqing Xu~* National Engineering Laboratory for Modern Silk,Department of Applied Biology,Medical College of Soochow University,Suzhou,Jiangsu 215123,China

【机构】 苏州大学基础医学与生物科学学院应用生物学系现代丝绸国家工程实验室；

【摘要】 家蚕卵滞育受亲代卵孵化后期的温度和光节律诱导。家蚕滞育性卵内酯酶A4(TIME-EA4)具有SOD活性和瞬时ATPase活性,后者被认为具滞育发育生物钟作用。为了解TIME-EA4生物钟活性是否依赖其基因表达,本文研究了滞育性蚕卵活化过程中Ea4基因转录水平与其生物钟酶活性的关系,调查了滞育诱导温度和光节律条件,对家蚕整个世代Ea4基因表达谱的影响。结果表明,15DD、25LL和20LD 3种经典滞育诱导发生条件之间,Ea4基因转录水平有显著差异,但没有典型的光照明暗节律和温度高低节律的转录水平振荡变化;EST表达谱和基因芯片表达谱结果显示,Ea4基因在吐丝期和变态期表达上调,组织特异性上调表达出现在表皮与头部。子代滞育性卵在盐酸孵化处理和5℃低温冷藏活化处理后,TIME-EA4 ATPase活性分别在处理后1.5h和13d瞬时出现后消失,此过程中没有检测到Ea4基因mRNA水平的提高。因此认为,家蚕滞育发育生物钟基因Ea4不是温度和光照授时因子的靶基因。更多还原

【Abstract】 Diapause in Bombyx mori eggs is induced by temperature and photoperiod at the stage of embryonic development in the maternal generation.In those diapause eggs,Esterase-A4 is suggested to serve as a diapause-termination timer(TIME-EA4),because its ATPase activity shows an interval-timer elevation after acid-treatment or chilling of eggs to break diapause.In order to clarify whether the timed ATPase activity of TIME-EA4 is related to its gene {EaA) expression,we analyzed EaA mRNA of eggs in diapause-inducing environmental conditions.RT-PCR analysis showed that EaA transcript levels were significantly different among eggs incubated under constant illumination at 25℃,in darkness at 15℃,or in light-dark cycles of 12:12hr at 20℃,but did not oscillate when photoperiod and temperature periodically oscillated.Furthermore, expressed sequence tag profile and gene microarray analysis demonstrated that Ea4 showed stage-specific and tissue-specific expression during postembryonic stages,high Ea4 mRNA in the spinning and eclosion stages, and in integument and head,but low in gonads of fifth-instar day-3 larvae.Then we analyzed the relationship between TIME-EA4 ATPase activities and EaA gene expression.The ATPase activities in diapause eggs laid by the resultant adults transiently elevated after treatments to break diapause,that is,at hour-1.5 after common-acid treatment and day-13 after chilling at 5℃.However,these elevations of enzyme activities were not accompanied by any increases in EaA mRNA levels.In conclusion,the termination of the Bombyx embryonic diapause is related to TIME-EA4,but not to its gene expression.更多还原