中文摘要：

Krüppel homolog 1（Kr-h1）是含有C2H2锌指结构的转录因子,在昆虫变态发育中起重要作用。从家蚕5龄第3天幼虫的表皮中克隆了Bm Kr-h1基因,该基因全长c DNA为1 918 bp,其中开放阅读框1 047 bp,GC含量42.2%,编码348个氨基酸。氨基酸序列比对分析发现大部分昆虫物种的Kr-h1都含有8个锌指结构,暗示该蛋白质的功能具有一定的保守性。通过生物信息学方法预测Bm Kr-h1不含信号肽和糖基化位点,但含有19个可能的磷酸化位点,暗示其活性可能受到磷酸化和去磷酸化修饰的影响。利用原核表达系统表达获得了可溶的Bm Kr-h1蛋白并制备了抗体。Western blot和半定量RT-PCR检测的结果显示,不论在mRNA水平还是蛋白质水平,Bm Kr-h1在家蚕幼虫5龄初期和吐丝期的翅原基都有较高水平表达,而在蛹期的表达量较低。用保幼激素（JH）类似物Methoprene和蜕皮激素（20E）分别注射家蚕5龄第3天幼虫,发现2种激素均能诱导蚕体内Bm Kr-h1的表达上调。免疫组织化学结果显示,Bm Kr-h1在5龄第3天幼虫各组织中的表达量很低,而在吐丝期的中肠、脂肪体和表皮中都有一定水平的表达,暗示其可能参与家蚕蜕皮变态的过程。上述结果表明Bm Kr-h1可以响应JH和20E的诱导,提示其在家蚕的变态发育中发挥作用。

英文摘要：

Krüppel homolog 1（ Kr-h1） is a transcription factor containing C2H2 zinc finger domain,which may play an important role in the metamorphosis of insects. In this study,Bm Kr-h1 gene was cloned from the epidermis tissue of day 3silkworm（ Bombyx mori） larva of the 5th instar. The full length c DNA of Bmkr-h1 is 1 918 bp long,containing an open reading frame of 1 047 bp. There is 42. 2% GC in its ORF region,which encodes 348 amino acids. Amino acid alignment revealed that most Kr-h1 proteins from insects contain eight zinc finger domain, indicating that the function of Kr-h1 are conservative. Bioinformatics analysis results showed that Bm Kr-h1 has no signal peptide and glycosylation site,but has 19 phosphorylation sites,suggesting that its activity might be affected by phosphorylation and dephosphorylation. Using the prokaryotic expression system,we expressed the soluble Bm Kr-h1 protein and prepared the relevant antibody. Western blottingand semi-quantitative RT-PCR results showed that Bm Kr-h1 expressed at high levels in the wing disc during the fifth larval stage and wandering stage,but at low level at the pupal stage both in the mRNA and protein levels. The expression of Bm Kr-h1 was up-regulated after day 3 silkworm larvae of the 5th instar were injected with juvenile hormone analog methoprene and ecdysone（ 20E）. The result of immunohistochemical localization showed that Bm Kr-h1 had trace expression in various tissues of day 3 of the 5th instar larvae,while it was expressed in the midgut,fat body and epidermis during the wandering stage,indicating that Bm Kr-h1 may be involved in molting and metamorphosis of silkworm. These results suggest that Bm Kr-h1 can respond to JH and 20 E,and plays an important role in metamorphosis of silkworm.