A Geminivirus DNA Replication Protein - Programming Its Plant Host

双生病毒 DNA 复制蛋白 - 对其植物宿主进行编程

• 批准号: 9809953
• 负责人: Linda Hanley-Bowdoin
• 金额: $ 33万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-15 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9809953&HistoricalAwards=false
• 关键词: Geminivirus; DNA; Replication; Protein; Programming

9809953 Hanley-Bowdoin Geminiviruses are a family of eukaryotic DNA viruses with single-stranded genomes that replicate through a rolling circle mechanism in nuclei of infected plant cells. They have small genomes, encode one protein that is essential for their replication, and rely on the replication machinery of their hosts. The overall goal of this research is to determine the mechanisms whereby geminiviruses recruit host DNA replication machinery. The investigator showed that geminivirus infection induces the accumulation of the host DNA synthesis protein, proliferating cell nuclear antigen (PCNA), in terminally differentiated plant cells. PCNA RNA levels and promoter activity are also elevated in infected tissue, demonstrating that geminiviruses can activate transcription of genes encoding DNA synthesis proteins in quiescent plant cells. The essential viral replication protein, AL1, is sufficient to induce the accumulation of PCNA in differentiated cells of transgenic plants, and thus may be analogous to the tumor antigen proteins of mammalian DNA viruses. In animal systems, DNA tumor viruses induce replication machinery in their host through a combination of common mechanisms. They encode proteins that directly activate transcription of genes encoding DNA synthesis proteins and/or interact with cell cycle regulatory factors to render quiescent cells competent for DNA replication. The investigator will determine whether AL1 uses similar or different mechanisms to induce PCNA transcription in differentiated plant cells by 1) determining whether interaction between AL1 and the cell cycle regulatory factor, retinoblastoma protein, is required for PCNA transcription, 2) asking whether multiple domains of AL1 contribute to PCNA transcriptional activation, and 3) identifying other plant proteins that interact with AL1 for PCNA induction. Geminiviruses are excellent model systems for studying eukaryotic DNA replication and cell cycle regulation, areas of study that have not been pursued extensively in plant systems. The ultimate g oals of the project are to elucidate the pathway whereby geminiviruses modify and maintain their host plants in an optimal state for viral DNA replication and to relate this pathway to plant cell cycle and transcriptional regulatory processes. The research will identify and begin to characterize components of the geminivirus/host regulatory network. The long term objectives are to understand how each component functions during geminivirus infection and in normal cellular processes. These experiments, which are based entirely on plant virus and host components, afford a rare opportunity to study plant cell cycle regulation directly. They will also increase our understanding of the basic mechanisms whereby eukaryotic viruses modify cellular processes and may illustrate fundamental similarities and/or differences between plants and animals.

9809953 Hanley-Bowdoin Geminiviruses是一个具有单链基因组的真核DNA病毒家族，通过感染植物细胞的细胞核中的滚动圆形机制复制。 它们具有小的基因组，编码一种对复制至关重要的蛋白质，并依靠宿主的复制机制。 这项研究的总体目标是确定双子病毒募集宿主DNA复制机制的机制。 研究者表明，双子病毒感染在末端分化的植物细胞中诱导宿主DNA合成蛋白，增殖细胞核抗原（PCNA）的积累。 在感染组织中，PCNA RNA水平和启动子活性也升高，表明双子病毒可以激活编码静态植物细胞中DNA合成蛋白的基因的转录。 必需的病毒复制蛋白AL1足以诱导PCNA在分化的转基因植物细胞中的积累，因此可能类似于哺乳动物DNA病毒的肿瘤抗原蛋白。 在动物系统中，DNA肿瘤病毒通过多种共同机制在其宿主中诱导复制机制。 它们编码蛋白质，这些蛋白质直接激活编码DNA合成蛋白的基因转录和/或与细胞周期调节因子相互作用，以使静止的细胞有能力用于DNA复制。 研究者将通过1）确定AL1是否使用类似或不同的机制在分化的植物细胞中诱导PCNA转录，确定AL1与细胞周期调节因子之间的相互作用是否需要PCNA转录的细胞周期调节因子，视网膜细胞瘤蛋白需要，2）询问AL1的多个域是否有助于PCNA转录激活，以及与其他植物蛋白相互作用的PCNA转录激活，以及与其他植物蛋白相互作用的人。 双子病毒是用于研究真核DNA复制和细胞周期调节的出色模型系统，研究领域尚未在植物系统中广泛追求。 该项目的最终g是阐明双子病毒在病毒DNA复制的最佳状态下修改和维护其宿主植物的途径，并将这种途径与植物细胞周期和转录调节过程相关联。 该研究将确定并开始表征双子病毒/主机监管网络的组成部分。 长期目标是了解双子病毒感染和正常细胞过程中每个组件的功能。 这些实验完全基于植物病毒和宿主成分，为直接研究植物细胞周期调节提供了难得的机会。 它们还将增加我们对真核病毒修改细胞过程的基本机制的理解，并可能说明动植物之间的基本相似性和/或差异。