诱导滞育的温度和光照节律对家蚕滞育激素基因Dh表达的影响  

Effect of Diapause-inducing Temperature and Photoperiod on the Expression of Diapause Hormone Gene Dh in the Silkworm,Bombyx mori

作　　者：韩慧慧[1] 徐丽[1] 陶卉[1] 司马杨虎[1,2] 徐世清[1,2] 

机构地区：[1]苏州大学医学部应用生物学系,江苏苏州215123 [2]现代丝绸国家工程实验室,江苏苏州215123

出　　处：《蚕业科学》2010年第6期930-936,共7页ACTA SERICOLOGICA SINICA

基　　金：国家自然科学基金项目(No.30771632);苏州大学重大应用研究培育项目(No.Q3034850)

摘　　要：滞育激素(DH)是导致家蚕滞育生理现象出现的关键因素。研究卵期不同温度和光照节律引起家蚕滞育激素基因Dh表达的变化,探讨温度和光照对家蚕滞育调控的机制。催青期25℃持续光照(25LL)条件下,蚕卵中Dh基因mRNA高水平稳定转录;而在15℃持续黑暗(15DD)条件下,蚕卵中只有痕迹量Dh基因mRNA存在;25LL或者20℃、光照与黑暗12h交替(20LD)条件下,胚胎发育至单眼着色后(有效积温2160℃.h以后)Dh基因mRNA转录水平显著上调,与此时期胚胎对诱导滞育的温度和光照节律更加敏感一致。从催青期开始整个世代的保护温度和光照节律,呈现高温25℃显著上调整个胚后时期Dh基因mRNA转录水平,光照上调蛹期与蛾期Dh基因mRNA转录水平,且高温的作用强于光照。5龄第3天幼虫的基因芯片表达谱显示,Dh基因mRNA转录水平存在显著的性别与组织差异,雌蚕多个组织中的Dh基因mRNA转录水平都显著低于雄蚕,卵巢中的Dh基因mRNA只有痕迹量。亲代卵的催青温度与光照节律决定子代卵的滞育性,也影响到Dh基因mRNA的转录水平;但子代卵内Dh基因mRNA转录水平高低不是蚕卵滞育与否的关键。推测家蚕Dh基因表达的性别差异及在早期蚕卵中表达特征与滞育性不一致的现象,可能与Dh基因的前体多肽翻译产物剪切有关。Diapause hormone （DH） is the key factor that leads to diapause in silkworm （Bombyx mori）.In present study,expressional variations of silkworm diapause hormone gene （Dh） caused by various temperature and photoperiod conditions were examined to explore the regulatory mechanism of temperature and illumination to silkworm diapause.The results showed that Dh was steadily and highly expressed in developmental embryos under constant illumination at 25 ℃ （25LL）,but lowly expressed under constant darkness at 15 ℃ （15DD）.Under 12 h illumination and 12 h darkness cycle at 20 ℃ （20LD） or 25LL,the Dh mRNA level of embryos was up-regulated significantly at the late developmental stage （after the effective accumulated temperature was beyond 2 160 ℃·h）,being consistent with the super sensitivity of embryos to external illumination and temperature at this stage.Dh was dramatically up-regulated at 25 ℃ during the postembryonic stage,and illumination could also up-regulate the Dh expression level during pupal and moth stages.And the regulation by high temperature was stronger than that by illumination.In addition,gene microarray analysis showed that Dh had sex-and tissue-specific expression characteristics on day 3 of the 5th instar larvae.The Dh gene＇s mRNA transcriptional levels in multiple tissues of female larvae were significantly lower than those of the male larvae,and were very low in ovary.The incubation temperature and photoperiod of parental eggs had influence on the diapause of offspring eggs,and also affected the mRNA level of Dh.However,the mRNA transcriptional level of Dh gene in offspring eggs was not the key factor to determine whether diapause of the eggs occurred.It was suggested that the sex difference of silkworm Dh gene expression and the discrepancy between the expression pattern of Dh gene in silkworm eggs and the diapause of the eggs were relaxed to splicing of precursor polypeptide of the Dh gene.

关 键 词：温度 光照 家蚕 滞育激素 基因表达 滞育发生 

分 类 号：S882[农业科学—特种经济动物饲养]