Interactions of the CA Protein in the Retrovirus Core

逆转录病毒核心中 CA 蛋白的相互作用

• 批准号: 6895277
• 负责人: REBECCA C. CRAVEN
• 金额: $ 24.89万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6895277
• 关键词: RNA directed DNA polymerase; Retroviridae; gene mutation; intermolecular interaction; mass spectrometry; ribonucleoproteins; virus RNA; virus genetics; virus protein; virus replication

DESCRIPTION (provided by applicant): The CA protein is the major structural protein of the retrovirus core, yet its contribution to the virus replication cycle has never been determined. In the mature virion core, CA forms a protein shell that surrounds the ribonucleoprotein (RNP) complex of viral RNA and replication enzymes. The function of this capsid-like shell is entirely unknown. However, several lines of evidence indicate that the integrity of CA and the shell it forms is in some way necessary for reverse transcription of the viral genome. We have previously demonstrated that conservative amino acid substitutions in the major homology region (MHR, a sequence shared by most retroviruses, retrotransposons, and hepadnaviruses) cause a serious deficit in DNA synthesis ability of the particles and a failure of the virus to infect. Since these particles contain all the necessary protein constituents as well as an intact RNA genome, it appears that the MHR and CA itself has a critical role in forming the constituents of the core into an effective DNA synthesis machine. A sequence similarity with the P proteins of paramyxo- and rhabdoviruses suggests the possibility that the CA protein acts directly to facilitate utilization of the genomic RNA template by participating as a non-catalytic component of the polymerase complex. Our previous genetic studies of the MHR have yielded at least four revertant viruses that carry unmapped suppressors that fall outside of the gag gene, providing a compelling argument for functional interactions of CA with one or more other constituents of the virion. The major goals of the proposed research will be to determine the identity of the suppressors responsible, to test predictions that CA is in direct contact with the viral RNP, and to identify other portions of the CA carboxy-terminal domain that cooperate with the MHR to facilitate these activities. Achieving these goals will be a major step toward understanding one of the most mysterious aspects of the retroviral life cycle and the ultimate identification of new strategies for antiviral therapies.

描述（由申请人提供）：CA蛋白是逆转录病毒核心的主要结构蛋白，但其对病毒复制周期的贡献从未确定。在成熟的病毒座核中，Ca形成了围绕病毒RNA和复制酶的核糖核蛋白（RNP）复合物的蛋白壳。这种类带状外壳的功能完全未知。然而，几条证据表明，CA及其形成的外壳的完整性在某种程度上是对病毒基因组进行逆转录的必要方式。我们以前已经证明，主要同源性区域中的保守氨基酸取代（MHR，大多数逆转录病毒，逆转录座和肝病病毒共享的序列）会导致颗粒的DNA合成能力严重不足，以及病毒失败的DNA合成能力。由于这些颗粒包含所有必要的蛋白质成分以及完整的RNA基因组，因此MHR和CA本身在将核心成分形成有效的DNA合成机中具有关键作用。与Paramyxo-和rhabdovirus的P蛋白的序列相似性表明，CA蛋白通过作为聚合酶复合物的非催化成分而直接作用于CA蛋白直接起作用，以促进基因组RNA模板的利用。我们以前对MHR的遗传研究至少产生了四种恢复病毒，这些病毒带有未塑造的抑制剂，这些抑制因子落在GAG基因之外，这为CA与病毒体的一个或多个其他成分的功能相互作用提供了令人信服的论点。拟议研究的主要目标是确定负责的抑制器的身份，以测试CA与病毒RNP直接接触的预测，并确定与MHR合作以促进这些活动的CA羧基末端域的其他部分。实现这些目标将是理解逆转录病毒生命周期中最神秘的方面之一，以及对抗病毒疗法的新策略的最终识别的重大步骤。