家蚕幼虫蜕皮前后头胸部蛋白质的差异表达分析

An Analysis on Differential Expression of Proteins in the Cephalothorax of Bombyx mori Larvae Before and After Molting

家蚕（Bombyx mori）属于完全变态昆虫,其幼虫需要经历3-4次入眠蜕皮才能结茧化蛹,已明确蜕皮过程受控于蚕体内蜕皮激素和保幼激素的含量,2种激素分别由位于头胸部的前胸腺和咽侧体分泌。为了从蛋白质水平解析家蚕蜕皮调控机制,应用双向电泳（2-DE）技术分别对各个龄期的将眠蚕、眠蚕和起蚕头胸部的总蛋白质进行分离,再以基质辅助激光解吸附电离飞行时间质谱（MALDI-TOF/TOF）对差异蛋白点进行鉴定。对各时期幼虫头胸部总蛋白质的2-DE图谱比对,共发现9个在眠期上调表达的差异蛋白点,经质谱鉴定分别为富含亮氨酸的损伤DNA结合蛋白、含有DEAD/H结构域的SWI/SNF相关的核小体重塑调节因子、精子生成相关蛋白、呼吸相关蛋白和泛素蛋白连接酶。初步推断这些差异表达蛋白不仅分别在家蚕的生理代谢、细胞凋亡、生殖发育、生长调节等生物学过程发挥作用,而且在幼虫的蜕皮过程中扮演了重要角色。

The silkworm（ Bombyx mori）,a kind of holometabolous insect,can produce cocoon and transform into pupa after three or four times of molting. It has been widely accepted that the process of molting is regulated by the contents of ecdysone and juvenile hormone. They are secreted by prothoracic gland and corpora allata located in the cephalothorax,respectively. To elucidate the regulatory mechanism of molting in silkworm at the protein level,this study separated total proteins in the head and thorax of pre-molting,molting and newly exuviated silkworm larvae at different instars by two-dimensional gel electrophoresis（ 2-DE）,and identified the differential proteins by matrix-assisted laser desorption ionizationand time of flight mass spectrometry（ MALDI-TOF/ TOF）.After comparative analysis of total proteins in the 2-DE images at different stages,nine differential protein spots were found to be up-regulated during the molting stage.The results of mass spectrometric identification showed that they were leucine-rich repeat-containing protein DDB,SWI / SNF-related matrix associated actin dependent regulator of chromatin subfamily A containing DEAD / H box 1homolog,spermatogenesis associated protein 5-like,pro-teins related with gasp,and E3 ubiquitin-protein ligase RBBP6-like,respectively. It was preliminarily inferred that these differential proteins play important roles not only in biological processes including physiological metabolism,apoptosis,reproductive development,and growth regulation,but also in the molting process of silkworm larvae.