Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China.
J Insect Physiol. 2010 Jul;56(7):788-99. doi: 10.1016/j.jinsphys.2010.02.001. Epub 2010 Feb 17.
A full-length cDNA (Slctlp2) encoding a chymotrypsin-like serine protease was cloned from Spodoptera litura. This cDNA encoded a putative serine protease with a predicted molecular mass of 30.6kDa, which contained a serine protease catalytic motif GDSGGPL. Temporal and spatial expression of Slctlp2 mRNA and protein detected by Northern blotting, RT-PCR, qPCR and Western blotting analyses revealed that both Slctlp2 mRNA and protein were mainly present in the foregut and midgut of the 5th and 6th instar larvae during the feeding stages. In situ hybridization and immunohistochemistry confirmed that both Slctlp2 mRNA and protein were predominately present in the midgut. Expression of the gene was not induced by bacterial infection. Juvenile hormone III induced the gene expression, while 20-hydroxyecdysone had no impact on the expression. The expression of Slctlp2 mRNA and protein was down-regulated by starvation but up-regulated by re-feeding. The SlCTLP2 protein was detected in the lumen residues of the anterior, middle and posterior midgut and feces of the feeding 6th instar larvae, suggesting that it was secreted from the epithelium into the lumen of the gut. The results suggest that this Slctlp2 gene may be involved in digestive process of food proteins during the feeding stages of the larval development.
从斜纹夜蛾中克隆到一个全长 cDNA（Slctlp2），该 cDNA 编码一种糜蛋白酶样丝氨酸蛋白酶。该 cDNA 编码的假定丝氨酸蛋白酶预测相对分子质量为 30.6kDa，含有丝氨酸蛋白酶催化基序 GDSGGPL。通过 Northern blot、RT-PCR、qPCR 和 Western blot 分析检测 Slctlp2 mRNA 和蛋白的时空表达，发现 Slctlp2 mRNA 和蛋白主要存在于 5 龄和 6 龄幼虫取食期的前肠和中肠。原位杂交和免疫组织化学证实 Slctlp2 mRNA 和蛋白主要存在于中肠。该基因的表达不受细菌感染诱导。保幼激素 III 诱导该基因表达，而 20-羟基蜕皮酮对其表达没有影响。饥饿使 Slctlp2 mRNA 和蛋白的表达下调，但再喂养使其表达上调。在取食 6 龄幼虫的前、中、后肠腔残留物和粪便中检测到 SlCTLP2 蛋白，表明它从肠上皮细胞分泌到肠腔中。结果表明，该 Slctlp2 基因可能参与幼虫发育取食期的食物蛋白消化过程。
