A surface-exposed region of the UL37 protein that is essential for alphaherpesvirus neuroinvasion

 描述(申请人提供)：甲型疱疹病毒是一种病原体，可以熟练地入侵具有免疫能力的宿主的神经系统。这些神经侵袭性疱疹病毒从感觉神经元传播到眼睛、大脑或从母亲传播到新生儿，是导致发病率和死亡率的重要原因。单纯疱疹病毒1型(HSV-1)和伪狂犬病病毒(PRV)是哺乳动物神经侵袭性疱疹病毒(单纯疱疹病毒和水痘病毒)两个属中具有代表性的成员。这些病毒依靠传播到神经系统来建立终身潜伏感染，但对这一显著特征背后的分子机制知之甚少。UL37蛋白是甲型疱疹病毒病毒粒子的保守结构成分。我们的实验室最近在该蛋白的氨基末端半部分发现了三个高度保守的表面暴露区域。作为这项提议的初步数据的一部分，我证明了伪狂犬病病毒(PRV)在这些区域之一突变，命名为R2，在上皮细胞中复制到接近野生型滴度，但未能入侵 由于轴突内持续逆行运输的缺陷，宿主神经系统。这一建议是建立在假设UL37执行神经传递所需的关键效应器功能的基础上的。拟议的实验将检验这种突变体在长距离轴突运输中有缺陷的机制，并确定效应器 R2区的功能在人类病原体HSV-1中是保守的。R2突变体由于其在外周细胞中的复制而具有产生强大免疫反应的能力。这一特性再加上神经侵袭能力的丧失，使R2突变体独特地适合通过防止潜伏期的建立来推进针对人类和兽医甲型疱疹病毒感染的减毒活疫苗的开发。

 DESCRIPTION (provided by applicant): Alphaherpesviruses are pathogens that proficiently invade the nervous system of an immunocompetent host. Spread of these neuroinvasive herpesviruses from sensory neurons to the eye, brain or from mother to newborn, are significant causes of morbidity and mortality. Herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PRV) are representative members of the two genuses of mammalian neuroinvasive herpesviruses (simplexviruses & varicelloviruses). These viruses rely on spread to the nervous system to establish life-long latent infections, yet very little is known regarding the molecular mechanisms that underlie this remarkable trait. The UL37 protein is a conserved structural component of the alphaherpesvirus virion. Our lab recently identified three highly conserved surface-exposed regions in the amino terminal half of this protein. As part of my preliminary data for this proposal I demonstrated that pseudorabies virus (PRV) mutated in one of these regions, designated R2, replicates to near wild-type titers in epithelial cells, however fails to invade the host nervous system due to a defect in sustained retrograde transport within the axon. This proposal is founded on the hypothesis that UL37 performs critical effector functions that are required during neural delivery. The experiments proposed will examine the mechanism by which this mutant is defective at long distance axon transport as well as determine if the effector functions of the R2 region are conserved in the human pathogen, HSV-1. The R2 mutant has the capacity to generate a robust immune response due to its replication in peripheral cells. This property in combination with the loss in neuroinvasive capabilities makes the R2 mutant uniquely suited to advance the development of live-attenuated vaccines against both human and veterinary alphaherpesvirus infection by preventing latency establishment.