The Relationships of parasite Polydnaviruses and Venom Secretions to Host Immunosuppression and Development Arrest

寄生虫多DNA病毒和毒液分泌与宿主免疫抑制和发育停滞的关系

• 批准号: 9018020
• 负责人: Max Summers
• 金额: $ 4万
• 依托单位: Texas A&M Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-09-01 至 1992-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9018020&HistoricalAwards=false
• 关键词: Relationships; parasite; Polydnaviruses; Venom; Secretions

Some insect parasites that lay eggs in their hosts inject special secretions into the host along with their eggs. These secretions appear to have two effects. First, they protect the parasite's eggs from the host's immune defenses and second, they cause arrest of host development. For Campoletis sonorensis, both phenomena may be induced by a polydnavirus (PDV). PDV is the only animal DNA virus with a heterogeneous, segmented genome. Several viral gene families have been identified, and viral gene expression is tissue and/or host specific. Through evolution the parasite has acquired the ability, which is essential for its survival, to assemble, amplify and transfer this genetic information in a viral form to another eucaryotic host. Prior results from this laboratory have shown that one family of the venom-related (VR) wasp and polydnavirus (PDV) genes belong to the "DEAD" protein family whose members are implicated in the control of gene expression at the levels of translation and splicing. This suggests that these unique genes may regulate splicing or translation of wasp and/or host genes. Recent studies show also that three CsPDV genes contain a cysteine motif characteristic of peptide toxins. The presence of this motif may reflect a function as a ligand of cell surface receptors which may correlate with parasite survival. Polydnavirus expression products and venom secretions may be more related in "host regulation" phenomena than previously thought.The next stage of this research will be directed toward identifying these expression products and determining their functional significance. The life cycles of certain wasps involve a stage at which they are parasites on other insects such as moths. The adult wasp lays its eggs by injecting them into the body of a larval moth. Special secretions are injected along with the eggs. These secretions contain factors that protect the eggs from the host's immune defense mechanisms and arrest the development of the host. In at least some such parasite/host relationships, a virus is an important component of this interaction. This laboratory is approaching this complex problem by identifying parasite and virus genes and gene products involved in this relationship. The overall goal of this research is to understand the molecular basis of the parasite-induced avoidance of host insect defense systems.

一些在寄主体内产卵的昆虫寄生虫会将特殊的分泌物与卵子一起注入寄主。这些分泌物似乎有两种效果。首先，它们保护寄生虫的卵免受宿主的免疫防御，其次，它们导致宿主发育受阻。对于松突弯孢菌，这两种现象都可能是由多聚核糖核酸病毒(PDV)诱导的。PDV是唯一一种具有异质性、节段性基因组的动物DNA病毒。目前已鉴定出几个病毒基因家族，并且病毒基因的表达具有组织和/或宿主特异性。通过进化，寄生虫已经获得了对其生存至关重要的能力，即组装、放大并以病毒形式将这些遗传信息转移到另一个真核宿主。本实验室先前的研究结果表明，毒液相关(VR)黄蜂和多聚核糖核酸病毒(PDV)基因中的一个家族属于死亡蛋白家族，其成员参与了翻译和剪接水平的基因表达调控。这表明这些独特的基因可能调控黄蜂和/或寄主基因的剪接或翻译。最近的研究还表明，三个CsPDV基因都含有半胱氨酸基序，这是多肽毒素的特征。这个基序的存在可能反映了作为细胞表面受体配体的功能，这可能与寄生虫的生存相关。多聚核糖核酸病毒的表达产物和毒液分泌在“宿主调节”现象中的关系可能比以前认为的更大。下一阶段的研究将致力于鉴定这些表达产物并确定它们的功能意义。某些黄蜂的生命周期涉及到一个阶段，在这个阶段，它们是寄生在其他昆虫(如飞蛾)上的。成年黄蜂通过将卵注入幼蛾体内来产卵。与卵子一起注射的是特殊的分泌物。这些分泌物含有保护卵子免受宿主免疫防御机制影响的因子，并阻止宿主的发育。至少在一些这样的寄生虫/宿主关系中，病毒是这种相互作用的重要组成部分。这个实验室正在通过鉴定寄生虫和病毒基因以及与这种关系有关的基因产物来解决这个复杂的问题。本研究的总体目标是了解寄生虫诱导的逃避寄主昆虫防御系统的分子基础。