E74 exhibits stage-specific hormonal regulation in the epidermis of the tobacco hornworm, Manduca sexta
E74 exhibits stage-specific hormonal regulation in the epidermis of the tobacco hornworm, Manduca sexta
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DOI：
10.1016/s0012-1606(03)00105-2
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发表时间：
2003-06-01
影响因子：
2.7
通讯作者：
Riddiford, LM
中科院分区：
文献类型：
--
作者：
Stilwell, GE;Nelson, CA;Riddiford, LM
转录因子E74是果蝇变态过程中蜕皮激素诱导表达的早期基因之一。本文报道了烟草天蛾（Manducasexta，MsE 74）E74基因的克隆及其激素调控。MsE 74与D.在蛋白质的DNA结合ETS结构域内的黑腹。MsE 74 A和MsE 74 B的5 '-同种型特异性区域具有显著较低的序列相似性（30-40%）。通过北方印迹分析的发育表达揭示，在第5龄幼虫期间，MsE 74 B的表达与蛹在第3天的定型有关，并且在12小时内被低水平的20-羟基蜕皮激素（20-hydroxyecdysone，20 E）诱导至最高水平，并被生理相关水平的保幼激素I（juvenile hormone I，JH I）抑制。诱导与蛹定型相关的Broad转录因子（Zhou和Riddiford，2001）。相比之下，MsE 74 A在幼虫和蛹蜕皮后期表达，此时蜕皮类固醇滴度已下降至低水平，而在成虫蜕皮中，蜕皮类固醇滴度刚开始下降。成虫蜕皮期间的这种时间变化似乎不是由于JH的缺乏，因为在allatectomized动物的蛹蜕皮期间没有变化。当第4或第5龄幼虫表皮被包裹并进行激素处理时，MsE 74 A诱导仅发生在暴露于20 E之后，随后将其去除。因此，MsE 74 B似乎有一个类似的作用，在变态的开始在曼杜卡果蝇，而MsE 74 A的调节不同的蛹在曼杜卡比在pupariation在果蝇。
The transcription factor E74 is one of the early genes induced by ecdysteroids during metamorphosis of Drosophila melanogaster. Here, we report the cloning and hormonal regulation of E74 from the tobacco hornworm, Manduca sexta (MsE74). MsE74 is 98% identical to that of D. melanogaster within the DNA-binding ETS domain of the protein. The 5'-isoform-specific regions of MsE74A and MsE74B share significantly lower sequence similarity (30-40%). Developmental expression by Northern blot analysis reveals that, during the 5th larval instar, MsE74B expression correlates with pupal commitment on day 3 and is induced to maximal levels within 12h by low levels of 20-hydroxyecdysone (20E) and repressed by physiologically relevant levels of juvenile hormone I (JH I).Immunocytochemical analysis shows that MsE74B appears in the epidermis before the 20E-induced Broad transcription factor that is correlated with pupal commitment (Zhou and Riddiford, 2001). In contrast, MsE74A is expressed late in the larval and the pupal molts when the ecdysteroid titer has declined to low levels and in the adult molt just as the ecdysteroid titer begins to decline. This change in timing during the adult molt appears not to be due to the absence of JH as there was no change during the pupal molt of allatectomized animals. When either 4th or 5th instar larval epidermis was explanted and subjected to hormonal manipulations, MsE74A induction occurred only after exposure to 20E followed by its removal. Thus, MsE74B appears to have a similar role at the onset of metamorphosis in Manduca as it does in Drosophila, whereas MsE74A is regulated differently at pupation in Manduca than at pupariation in Drosophila.