Parvovirus RNA Processing

描述（由申请人提供）：在最近的授权期内，我们几乎完成了细小病毒科所有五个属的代表性成员的转录谱的表征，我们的分析揭示了比以前想象的更大的多样性或遗传策略。我们的研究清楚地表明，在细小病毒的5个属中，有3个属的成员，红病毒、安多病毒，可能还有博卡病毒群，在它们的左端只使用一个启动子，因此它们的表达调控必须完全是转录后的。我们的工作还表明，除了红病毒，依赖病毒、Amdovirus和bocavvirus属的成员也在基因组中心的一个位点上使用选择性聚腺苷化。因此，作为控制细小病毒基因表达的一种手段，可选择的内部聚腺苷酸化已经成为一种规则，而不是例外。此外，现在很清楚的是，细小病毒的结构蛋白和非结构蛋白的表达比以前认识到的更多地使用了替代翻译策略——考虑到它们需要从如此紧凑的基因组中表达复杂的基因表达模式，这也许并不奇怪。细小病毒表达策略变异的发现也强调了一些在MVM、AAV和B19原型研究中未预测到的蛋白质的潜在重要性。例如，GPV大Rep 1蛋白作为其衣壳蛋白编码基因的转录激活因子，但其作用模式似乎与AAV2 Rep蛋白或MVM NS1不同。此外，牛细小病毒BPV和人细小病毒HBoV都大量表达了bocavavirus NP1蛋白，这表明它可能是许多细小病毒基因组中心的ORF编码的细小病毒蛋白的原型。在这个申请中，我们建议：1)完成所有细小病毒科的代表性样本的转录谱的测定；2。表征新发现的基因图谱所要求的新表达策略；ⅲ。确定新的细小病毒蛋白的功能，这些新的谱图明确了它们的重要性。这些研究将极大地促进我们对这一重要病毒群的理解，为理解细小病毒科成员之间的进化关系提供一个框架，并像过去的情况一样，继续揭示有吸引力的、可处理的模型来检查基本的细胞功能。

DESCRIPTION (provided by applicant): Over the last granting period we have nearly completed characterization of the transcription profiles of representative members of all five genera of the Parvovirinae, and our analyses have revealed a much greater variety or genetic strategies than previously thought. Our work makes clear that members of three of the five parvovirus genera, the Erythrovirus, Amdovirus, and probably Bocavirus groups use only a single promoter in their left hand end, and so regulation of their expression must be exclusively posttranscriptional. Our work has also shown that in addition to the Erythroviruses, members of the Dependovirus, Amdovirus and Bocavirus genera also use alternative polyadenylation at a site within the center of the genome. Thus, alternative internal polyadenylation as a means to govern parvovirus gene expression has emerged as the rule rather than the exception. In addition, it is now clear that the parvoviruses make greater use of alternative translation strategies for their expression than previously appreciated, both for their structural and nonstructural proteins - which is perhaps not surprising, given their need to express complex patterns of gene expression from such compact genomes. Discovery of the variation in parvovirus expression strategies has also underscored the potential importance of a number of proteins not predicted from studies on the prototypes MVM, AAV and B19. For example, the GPV large Rep 1 protein acts as a transcriptional activator of its capsid protein-encoding gene, yet seems to be distinct in its mode of action from either the AAV2 Rep protein or MVM NS1. Additionally, the Bocavirus NP1 protein is abundantly expressed by both bovine parvovirus BPV and the human bocavirus HBoV, suggesting it may be a prototype of parvovirus proteins encoded by an ORF in the center of many parvovirus genomes. In this application we propose to I.) complete the determination of the transcription profiles of representative examples of all the Parvovirinae genera; II. characterize new expression strategies mandated by the newly identified genetic profiles; and III. determine the function of novel parvoviral proteins whose importance these new profiles make clear. These studies will significantly advance our understanding of this important group of viruses, provide a framework for understanding the evolutionary relationships between members of the Parvovirinae, and as has been the case in the past, continue to reveal attractive, tractable models to examine basic cellular functions.