家蚕5龄幼虫后部丝腺细胞酶基因表达的比较分析

基于了解家蚕后部丝腺细胞分泌丝素蛋白基因的表达调控信息,阐明蚕茧高产的机理,根据EST分析结果,分析了家蚕5龄幼虫不同发育时期后部丝腺细胞中酶基因的表达谱特征。发现家蚕5龄幼虫第1天和第5天的生理生化反应涉及氧化还原酶的数量最多,达到30个,转移酶数量达28个,水解酶数量达22个,合成酶数量达12个,裂合酶数量达6个,异构酶数量最少,只有4个。这6种酶基因在家蚕5龄第1天和第5天之间表达差异不大,表达频率超过10次的酶只有细胞色素C氧化酶亚基Ⅰ、细胞色素C氧化酶亚基Ⅲ、S腺苷甲硫氨酸合成酶和肽基脯氨酸顺反异构酶。上述结果暗示家蚕5龄不同时期,丝素蛋白合成能力的差异与酶分子的数量关系不密切。

Comparative Analysis of Gene Expression of Enzymes in Posterior Silkgland Cells of Silkworm,Bombyx mori,Fifth Instar Larva

The gene expression analysis of the enzymes expressed in silkgland cells would tell us more details about the expressions and the regulation of genes,and can also be helpful to illustrate the mechanism of the silk high yield. The gene expression characters of those enzymes have been analyzed,which expressed in silkgland during differert periods of the fifth-instar,basis on the ESTs analysis. Result demonstrated that in the 1~st day and 5~th day in fifth-instar,the oxidoreductase expessed most frequently among all the enzymes related to the physiological and biochemical reactions occurred in the silkworm larva,and the number of which reached 30,that there are 28 transferases,22 hydrolase,12 synthetases,6 lyases,and 4 isomerases. The difference of the expression quantity of above mentioned 6 kinds of enzymes are not so distinct between 1~st day and 5~th day,only four enzymes,Cytochrome C oxidase subunit Ⅰ,Cytochrome C oxidase subunit Ⅲ,S-adenosylmethionine synthetase and peptidyl prolyl cis-trans isomerase expressed over 10 times during the two stage. The results suggest that the synthesizing capability of silk fibroin don't keep close relation to the quantity of enzyme molecule.