Genetic Basis of Drug Resistant Mutants of B Virus

描述（由申请方提供）：猴B病毒（BV）是猕猴的正常病原体，与人单纯疱疹病毒（HSV）密切相关。虽然BV在猕猴中不是一种严重的感染，但当传播给人类时，它很容易侵入中枢神经系统，如果不治疗，死亡率约为80%。由于BV感染的严重性，该病毒已被列入CDC选择代理列表作为潜在的生物恐怖主义代理。化学治疗是控制人类BV感染的唯一选择，但对各种药物对BV的疗效知之甚少。目前对BV感染的治疗基本上利用已知对HSV安全有效的药物，假设它们对BV也有效，因为病毒是相关的。我们最近测试了一些核苷类似物对BV的疗效。在这些研究的过程中，分离出两种天然存在的耐药变体（PCVr和GCVr）。在HSV中，赋予对无环核苷抗性的所有突变都发生在病毒胸苷激酶（TK）和/或DNA聚合酶基因中。这两个BV突变体的TK和DNA pol基因的测序显示，它们与亲本野生型病毒基因的序列相同。因此，一些其他病毒基因似乎参与决定这些BV分离株的耐药性。本申请将鉴定导致这些BV分离株耐药性的病毒基因。使用共转染程序，我们将构建重组病毒，以定位病毒基因组中含有耐药性位点的区域。一旦这个区域被定位，DNA测序将确定定义耐药性的精确序列差异。了解BV耐药相关基因将有助于对相关机制进行预测，并为进一步研究这些假设打开大门。所获得的知识也可能最终导致更好地了解BV对有效抗HSV药物的相对耐药性，并开发更有效的治疗BV感染的药物。

DESCRIPTION (provided by applicant): Monkey B virus (BV) is a normal pathogen of macaque monkeys that is closely related to human herpes simplex virus (HSV). Although BV is not a serious infection in macaques, when transmitted to humans it readily invades the central nervous system and, left untreated, has a fatality rate of approximately 80%. Due to the severity of BV infections, this virus has been included on the CDC Select Agent list as a potential bioterrorism agent. Chemotherapeutic treatment is the only option for controlling human BV infections, yet little is know about the efficacy of various drugs against BV. Current treatment for BV infections essentially utilizes drugs known to be safe and effective against HSV, the assumption being that they are also effective against BV since the viruses are related. We recently tested the efficacy of a number of nucleoside analogs against BV. In the course of these studies, two naturally occurring drug-resistant variants (PCVr & GCVr) were isolated. In HSV, all mutations conferring resistance to acyclo-nucleosides occur in the viral thymidine kinase (TK) and/or DNA polymerase genes. Sequencing of the TK and DNA pol genes of these two BV mutants revealed that they were identical to the sequence of the parental wild-type virus genes. Thus, some other virus gene(s) appears to be involved in determining the drug resistance of these BV isolates. This application will identify the viral gene(s) that are responsible for the drug resistance of these BV isolates. Using a co-transfection procedure, we will construct recombinant viruses to locate the region of the viral genome containing the drug resistance locus. Once this region has been localized, DNA sequencing will identify the precise sequence difference that defines drug resistance. Knowing the gene(s) involved in drug resistance of BV will allow some predictions to be made as to the mechanism involved and open the door to additional studies to test these hypotheses. The knowledge gained may also eventually lead to a better understanding of the comparative resistance of BV to drugs effective against HSV and to the development of more effective drugs for treatment of BV infections.