昆虫杆状病毒几丁质酶及其应用研究进展  

Baculovirus chitinase:Advances in research and application

作　　者：刘艳荷[1] 方继朝[1] 郭慧芳[1] 

机构地区：[1]江苏省农业科学院植物保护研究所

出　　处：《昆虫学报》2008年第4期430-436,共7页Acta Entomologica Sinica

基　　金：中国博士后科学基金项目(20060390946);江苏省博士后基金;江苏省农业科技创新资金项目(cx(07)606)

摘　　要：杆状病毒几丁质酶基因(chitinase,ChiA)是晚期表达的非必需基因,高度保守。表达产物几丁质酶分为3个区:N-端信号肽区,中部酶活性区和C-末端酶内质网结合区。该酶同时具有内切和外切几丁质酶活性,主要功能是水解昆虫体内的几丁质,促进虫体液化;作为组织蛋白酶原(pro-V-Cath)的分子伴侣,参与其加工和运输过程;影响多角体的形成,并与细胞的裂解有关;还与病毒侵染机制相关联。杆状病毒ChiA与细菌ChiA源于共同的祖先,而昆虫ChiA则可能直接来自杆状病毒。在害虫生物防治中,杆状病毒ChiA可直接作为杀虫剂,或作为苏云金杆菌和杆状病毒等微生物杀虫剂的增效剂使用;杆状病毒ChiA可转入植物,获得具有持续杀虫及抗病活性的转基因植物;将杆状病毒ChiA的内质网定位序列删除、突变,或在病毒基因组中插入外源ChiA,重组病毒的杀虫活性增强。通过基因工程手段,删除病毒基因组ChiA或V-Cath,可改善杆状病毒表达系统对分泌蛋白和膜结合蛋白的表达。The chitinase gene of baculovirus is the gene that is not essential for the virus replication. It is expressed in the late phase of the virus replication in insect cells, and it is highly conservative. The chitinase contains three functional regions： N-terminal secretion signal peptide, central active region that includes the active site of family 18 chitinases and a functional C-terminal endoplasmic reticulum （ER）-retention sequence. The enzyme possesses high performance of both exo- and endo-chitinase activity, which can hydrolyze inherent chitin in insect body, and promote liquefaction of the host after death. The chitinase may also serve as a molecular chaperone of pro-V-Cath, the precursor of V-Cath, for its proper folding and transportation in the ER. It has an influence on the polyhedra releasing and cell lysis. The chitinase is also relevant to the baculovirus infection. Phylogenetic analyses indicate that baculovirus acquires the chitinase gene from bacterium via horizontal gene transfer, but insect chitinase gene may directly come from baculovirus. For biological control of pests, the baculovirus chitinase can control insect pests as an insecticide, or work together with Bacillus thuringiensis or a baculovirus as its potentiator; the baculovirus chitinase gene can also be introduced into plants to get the transgenic plants that increase resistance against herbivorous pests and fungal pathogens without affecting non-target insects. The baculovirus chitinase ER-retention motif was deleted or modified, or heterologous chitinase was introduced into the baculovirus genome, which made the biological activity of the recombinant virus enhanced. Deletion of the chitinase and v-cathepsin genes from the baculovirus expression vector through genetic engineering has a positive effect on the integral membrane and secreted proteins.

关 键 词：生物防治 杆状病毒几丁质酶 功能 起源 增效作用 杀虫活性 应用 

分 类 号：Q965.8[生物学—昆虫学]