Encapsidation of adenovirus DNA

腺病毒是1953年首次发现的含有线性双链DNA基因组的小型无包膜病毒。人腺病毒与多种疾病相关，包括上呼吸道感染、胃肠道疾病和结膜炎。腺病毒感染是移植受者，特别是儿科患者的重要临床问题。多年来，这些病毒也被 用于研究DNA复制、RNA合成、蛋白质翻译、致癌转化和细胞凋亡的杰出模型系统，并且最近对腺病毒的兴趣由于其作为疫苗接种和人类基因转移研究的载体的潜力而扩大。病毒基因表达、基因组复制和病毒 组装都发生在受感染细胞的细胞核中。该项目的重点是病毒DNA的组装。该过程需要至少四个病毒元件：包装序列，其位于基因组的左端附近，并且由称为A重复的重复元件组成; IVa 2蛋白，其结合该区域中所需的序列基序，并且也是衣壳组装所需的; L4 22 kDa蛋白，其与DNA上的IVa 2蛋白形成复合物;和52/55 kDa蛋白，其结合DNA和IVa 2蛋白。该提案的目标是进一步阐明腺病毒使其DNA衣壳化的机制，以及该过程如何通过以下方式与衣壳形成相关联： IVa 2蛋白IVa 2蛋白促进衣壳组装和DNA包装的机制将通过检查含有IVa 2和L4 22 kDa蛋白的复合物的结构和通过解剖IVa 2蛋白的各种功能来研究。52/55 kDa蛋白的作用也将通过突变病毒的分析而被揭示。这些研究将推进我们对腺病毒如何 包装它的DNA并产生传染性病毒体。这些知识将适用于开发阻断这一过程的抗病毒药物，以及开发更安全的腺病毒载体和重组疫苗。

Adenoviruses are small, non-enveloped viruses containing a linear double stranded DNA genome that were first discovered in 1953. The human adenoviruses are associated with a variety of diseases including upper respiratory infections, gastrointestinal illness, and conjunctivitis. Adenovirus infections are a significant clinical problem in transplant recipients, particularly pediatric patients. For many years, these viruses have also been outstanding model systems for the study of DNA replication, RNA synthesis, protein translation, oncogenic transformation, and apoptosis, and more recently interest in adenovirus has expanded due to its potential as a vector for vaccination and human gene transfer studies. Viral gene expression, genome replication, and viral assembly all take place in the nucleus of the infected cell. This project addresses assembly with a focus on the encapsidation of viral DNA. This process requires at least four viral elements: the packaging sequence, which is located near the left end of the genome and is made up of repeated elements called A repeats; the IVa2 protein, which binds to required sequence motifs in this region and is also required for capsid assembly; the L4 22 kDa protein, which forms a complex with the IVa2 protein on the DNA; and the 52/55 kDa protein, which binds both the DNA and the IVa2 protein. The goals of this proposal are to elucidate further the mechanism by which adenovirus encapsidates its DNA, and how this process is linked to capsid formation by the IVa2 protein. The mechanism by which the IVa2 protein facilitates capsid assembly and DNA packaging will be studied by examining the structure of complexes containing the IVa2 and L4 22 kDa proteins and by dissecting the various functions of the IVa2 protein. The role of the 52/55 kDa protein will also be uncovered through the analysis of mutant viruses. These studies will advance our basic understanding of how adenovirus packages its DNA and produces infectious virions. This knowledge will be applicable to the development of anti-viral drugs that block this process, as well as to the development of safer adenovirus vectors and recombinant vaccines.