The impacts of classical insect hormones on the expression profiles of a new digestive trypsin‐like protease (TLP) from the cotton bollworm, Helicoverpa armigera
The impacts of classical insect hormones on the expression profiles of a new digestive trypsin‐like protease (TLP) from the cotton bollworm, Helicoverpa armigera
复制标题
DOI：
10.1111/j.1365-2583.2009.00884.x
复制
发表时间：
2009-08
影响因子：
2.6
通讯作者：
Yi-Peng Sui;J‐X. Wang;X‐F. Zhao
中科院分区：
文献类型：
--
作者：
Yi-Peng Sui;J‐X. Wang;X‐F. Zhao
胰蛋白酶在昆虫中肠的蛋白质消化中起着重要的作用。从棉铃虫基因组中克隆了1042bp的全长c DNA。该基因编码一个32 kDa的蛋白质，预测等电点为5.7。该蛋白的氨基酸序列含有类胰酶丝氨酸蛋白酶结构域，命名为Ha-TLP。该基因的表达具有组织特异性，Ha-TLP的转录本仅存在于中肠，而在5龄幼虫的头胸、珠被、脂肪体和血细胞中未见表达，在取食幼虫和蜕皮幼虫中的表达水平相近。在中肠，基因转录水平从6龄幼虫进入游走期72h开始下降，从6龄96h开始消失，一直持续到蛹期。免疫组织化学方法检测到Ha-TLP位于6龄取食期幼虫中肠上皮细胞的胞浆内。Ha-TLP的表达可被保幼激素(JH)类似物甲基丁二烯上调，被20-羟基蜕皮酮(20E)下调。这些事实表明，Ha-TLP参与了幼虫生长过程中的食物消化，并可能在体内被JH上调，而被额外的20E抑制。
Trypsin proteinases perform important roles in the protein digestion of an insect midgut. A 1042 bp full‐length cDNA was cloned from Helicoverpa armigera. The gene encoded a 32 kDa protein, with a predicted isoelectric point of 5.7. The amino acid sequence of the protein had a trypsin‐like serine protease domain, and the gene was named Ha‐TLP. The expression of the gene was tissue‐specific and the transcript of Ha‐TLP existed only in the midgut and was not found in the head‐thorax, integument, fat body and haemocytes from 5th instar larvae, with similar expression levels between those in feeding larvae and in molting larvae. In the midgut, the gene transcription level declined from 6th instar 72 h after the larvae entered the wandering stage, and disappeared from 6th instar at 96 h until the pupal stage. By immunohistochemistry, Ha‐TLP was detected in the cytoplasm of the midgut epithelial cells of the 6th instar feeding stage worms. The expression of Ha‐TLP could be up‐regulated by a juvenile hormone (JH) analog methoprene and down‐regulated by 20‐hydroxyecdysone (20E). These facts indicate that Ha‐TLP was involved in food digestion during larval growth and probably up‐regulated by JH and suppressed by extra 20E in vivo.