The Molecular Biology of Polydnavirus Gene Organization and Expression in Campoletis Sonorensis and Heliothis Virescens

寄生在其寄主昆虫上的寄生蜂的成功寄生依赖于多核糖核酸病毒在产卵过程中与寄生虫卵的转移和表达。该病毒及其生活史在两个主要方面是独一无二的：1)它是一种DNA动物病毒，具有复杂的多部分基因组，由至少28个双链、共价闭合的DNA组成；2)该病毒与黄蜂昆虫具有明显的共生关系，并导致寄生宿主的某些变化，有效地损害宿主的细胞免疫防御，有利于寄生虫的成功发育。桑小蜂及其病毒(CSV)和寄主昆虫绿日夜蛾是在分子水平上研究最深入的寄生-病毒-寄主系统。将继续研究绘制多部分基因组的遗传组织图。这将通过物理作图和黄蜂昆虫和寄生宿主中转录产物的作图来完成。一旦绘制了图谱，这些被认为是干扰寄生昆虫细胞防御系统的重要因素的基因将被克隆，并研究病毒编码基因产品的功能和特性。研究的最终目的是确定该病毒的特定功能和在寄生昆虫取消细胞免疫反应中的作用机制(靶点和作用)。这应有助于阐明昆虫免疫防御系统，以及如何利用这些防御系统控制对公共卫生或农业具有重要意义的昆虫，或控制昆虫传播动植物病原体的能力。

The successful parasitism by a parasitic insect wasp of its host insect is dependent upon the transfer and expression of a polydnavirus along with the parasite's egg during oviposition. The virus and its life cycle are unique in two major aspects: 1) it is a DNA animal virus with a complex multipartite genome consisting of at least 28 doublestranded, covalaently closed DNAs; 2) the virus has an apparent symbiotic relationship with the wasp insect and causes certain changes in the parasitized host effectively compromising the host's cellular immune defenses to favor the successful development of the parasite. The parasitic Campoletis sonorensis wasp, its virus (CsV), and the host insect, Heliothis virescens, is the most thoroughly studied parasite-virus-host system at the molecular level. Studies will be continued on mapping the genetic organization of the multipartite genome. This will be done by physical mapping and a mapping of the transcription products in the wasp insect and parasitized host. Once mapped those genes believed to be important factors interfering with the parasitized insect's cellular defense system will be cloned and studied for function and identity of viral encoded gene products. It is the ultimate goal of the research to identify the specific functions of the virus and mechanisms (target sites and effects) in the parasitized insect abrogating cellular immune response. This should lead to an elucidation of insect immunity defenses and how these may be manipulated for the control of insects of public health or agricultural importance, or for control of the ability of insects to transmit animal and plant pathogens.