Geminiviruses as Models for Plant Nuclear DNA Replication

双生病毒属是植物病毒的一个家族， 通过双链DNA复制的DNA基因组 感染细胞核中的中间体。 它们编码一个 单个蛋白质用于它们的复制，并且可以招募剩余的蛋白质。 复制机器的一部分 这些 特征表明，双生病毒是极好的模型 研究植物核DNA复制。 我们的总体目标是 研究的目的是了解介导 利用番茄金色花叶病毒（TGMV）复制双生病毒DNA 作为我们的原型。 我们将通过以下方法鉴定TGMV复制起点： 缺失分析和通过测定病毒DNA片段的 支持植物中非病毒DNA复制的能力 原生质体 TGMV的序列和结构要求 起源将通过分析包含以下内容的复制来表征 位点特异性突变。 我们对反式作用 参与复制的因素将集中在单个TGMV上， 编码的蛋白质，AL 1，复制所需的。 两个重要 我们要问的问题是AL 1是否特异性结合TGMV 复制起点及其在复制中的催化作用。 我们计划纯化AL 1，研究其催化性能， 确定它是否需要宿主蛋白质才能活动。 我们研究的长期目标是识别和表征 参与TGMV复制的植物蛋白，并确定 在正常细胞过程中的作用 *//

Geminiviruses constitute a family of plant viruses with single- stranded DNA genomes that replicate via double-stranded DNA intermediates in the nuclei of infected cells. They encode a single protein for their replication and can recruit the remainder of the replication machinery from their host. These characteristics suggest that geminiviruses are excellent models for studying plant nuclear DNA replication. The overall goal of our research is to understand the molecular events that mediate geminivirus DNA replication using tomato golden mosaic virus (TGMV) as our prototype. We will identify the TGMV replication origin by deletion analysis and by assaying viral DNA fragments for their ability to support replication of nonviral DNA in plant protoplasts. The sequence and structural requirements of the TGMV origin will be characterized by analyzing replications containing site-specific mutations. Our initial studies of trans-acting factors involved in replication will focus on the single TGMV- encoded protein, AL1, required for replication. Two important questions we will ask are does AL1 bind specifically to the TGMV replication origin and what is its catalytic role in replication. We plan to purify AL1, study its catalytic properties, and determine if it requires host proteins for activity. The long term goal of our research is to identify and characterize the plant proteins involved in TGMV replication and to determine their roles in normal cellular processes.***//