Structural and biochemical insights into multiple functions of HSV-1 UL21 in viral life cycle

 描述(申请人提供)：单纯疱疹病毒1型和2型(HSV-1和HSV-2)在美国非常流行，感染大多数人。这些病毒会导致终生的潜伏感染，并可能导致从轻微皮肤病到脑炎的疾病。不幸的是，预防性和治疗性治疗选择有限。HSV-1基因组衣壳和包膜之间的被膜蛋白网络可能调节感染机制的许多步骤。疱疹病毒学进展中的一个主要差距是，被膜蛋白的多种特定功能在很大程度上是未知的。确定这些蛋白质的多种功能对于全面了解病毒的生命周期至关重要。这项建议的重点是衣壳相关的被膜蛋白UL21，它在细胞质中作用以调节萌发，但在感染期间也在细胞核中发现。这项建议的目的是确定HSV-1 UL21的多种功能。这一提议的中心假设是UL21在HSV-1中具有新的和未被探索的核功能，与其结合核酸和定位于核缘的能力有关。这一假说将在两个特定的目标下进行检验：目标1将评估UL21与核酸和膜的结合，以分别描述UL21可能调节基因表达和核外泄的机制。此外，将在大肠杆菌中检测UL21对另一种病毒被蛋白UL16的直接转录效应。在目标2中，将通过对蛋白质表面的表征和在已知功能的蛋白质中寻找结构相似性来解决UL21及其C末端结构域的晶体结构并检查潜在的功能区域。这一建议具有重要意义，因为它将阐明以前隐藏在鲜为人知的被膜层中的重要功能，并帮助研究人员组装更完整的感染机制模型-这是设计新的治疗策略的必要步骤。

 DESCRIPTION (provided by applicant): Herpes Simplex Viruses Type 1 and 2 (HSV-1 and HSV-2) are extremely prevalent and infect most people in the United States. These viruses cause lifelong, latent infections and can cause diseases from minor skin lesions to encephalitis. Unfortunately, preventative and therapeutic treatment options are limited. Networks of tegument proteins between the HSV-1 genomic capsid and envelope are likely to regulate many steps of the infection mechanism. A major gap in the progression of herpesvirology is the fact that the multiple specific functions of tegument proteins are largely unknown. Characterizing the many functions of these proteins is crucial to a complete understanding of the viral lifecycle. This proposal focuses on capsid-associated tegument protein UL21 that acts in the cytoplasm to regulate budding but is also found in the nucleus during infection. The objective of this proposal is to identify the multiple functions of HSV-1 UL21. The central hypothesis of this proposal is that UL21 has novel and unexplored nuclear functions in HSV-1 related to its ability to bind nucleic acids and localize to the nuclear rim. The hypothesis will be examined in two Specific Aims: Aim 1 will assess the binding of UL21 to nucleic acids and membranes to describe the mechanisms by which UL21 may regulate gene expression and nuclear egress, respectively. Furthermore, direct transcriptional effects of UL21 on UL16, another viral tegument protein, will be assayed in E coli. In Aim 2, the crystal structure of UL21 and its C- terminal domain will be solved and inspected for potential functional regions by characterizing the protein surface and by searching for structural similarity in proteins of known function. This proposal is significant because it will elucidate important functions previously hidden in the poorly understood tegument layer and aid researchers in assembling a more complete model of the infection mechanism-a necessary step to design new therapeutic strategies.