Real and Apparent Complexity in Polydnavirus Genomes

多DNA病毒基因组的真实和表观复杂性

基本信息

批准号：
9603504
负责人：
Bruce Webb
金额：
$ 29.7万
依托单位：
University of Kentucky Research Foundation
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1997
资助国家：
美国
起止时间：
1997-03-15 至 2001-02-28
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9603504&HistoricalAwards=false
关键词：
Real Apparent Complexity Polydnavirus Genomes

项目摘要

Webb 9603504 Polydnavirus genomes and life cycles are complex. Campoletis somnorensis (PDV) has at least 28 DNA segments with genome size estimates in excess of 250 kb, of which the most abundantly expressed are nested. There is little understanding of the evolutionary pressures that have driven or allowed segmentation of the viral genome. PDVs are obligate symbionts of some parasitic hymenoptera and replicate asymptotically from integrated proviral DNA only in specialized calyx cells of the female reproductive tract. When the wasp paristizes the lepidopteran host, the virus genome invades the host, ceases replicating and viral genes are rapidly expressed at a constant level producing infection. Such viral gene expression is required for successful development of the endoparasitic wasp. The hypothesis that PDV genome segmentation has resulted from selective pressure for high level gene expression in parasitized insects will be tested by cloning and mapping genes on nested viral DNA segments, by evaluating a number of viral structural proteins and by manipulating the level of viral gene expression in host insects. The results of these studies will produce the first comprehensive characterization of a polydnavirus genome allowing critical evaluation of the linkage between segment nesting and levels of gene expression and may produce fundamental insights into the evolutionary forces that have shaped the genomes of polydnaviruses, the only group of segmented DNA viruses.

Webb 9603504 多DNA病毒基因组和生命周期很复杂。 Campoletis somnorensis (PDV) 至少有 28 个 DNA 片段，基因组大小估计超过 250 kb，其中表达最丰富的片段是嵌套的。人们对驱动或允许病毒基因组分割的进化压力知之甚少。 PDV 是某些寄生膜翅目的专性共生体，仅在雌性生殖道的专门花萼细胞中从整合的原病毒 DNA 中渐近复制。当黄蜂寄生鳞翅目宿主时，病毒基因组侵入宿主，停止复制，病毒基因以恒定水平快速表达，产生感染。这种病毒基因表达是内寄生黄蜂成功发育所必需的。 PDV 基因组分段是由寄生昆虫高水平基因表达的选择压力引起的假设，将通过在嵌套病毒 DNA 片段上克隆和定位基因、评估许多病毒结构蛋白以及操纵病毒基因表达水平来测试在宿主昆虫中。这些研究的结果将首次对多DNA病毒基因组进行全面表征，从而能够对片段嵌套和基因表达水平之间的联系进行严格评估，并可能对塑造多DNA病毒基因组的进化力量产生基本的见解，多DNA病毒是唯一的群体。分段DNA病毒。