Role of gammaherpesvirus lytic replication-associated genes in the establishment

描述（由申请人提供）：人类伽玛疱疹病毒感染与多种恶性肿瘤的发展有关。这些病毒对艾滋病毒感染者等免疫功能低下的患者构成特别重大的危险。伽玛疱疹病毒在B细胞中建立稳定的终身潜伏感染，提供终身病毒库，最终导致恶性疾病的发展。我们的长期目标是确定伽玛疱疹病毒在B细胞中建立潜伏期的机制，从而阐明开发预防伽玛疱疹病毒相关恶性肿瘤的新靶点。我们的方法是在小鼠γ疱疹病毒（gammaHV68, MHV68）系统中使用无法进行裂解复制的突变病毒来剖析潜伏期建立的最早事件。通过比较早期和晚期裂解基因突变的病毒，我们发现了裂解复制相关基因产物在B细胞潜伏期建立中的惊人作用。我们假设这些关键的裂解基因产物对于诱导表观遗传修饰至关重要，而表观遗传修饰对于潜伏病毒发作的保留至关重要。本提案的目标是确定在B细胞感染后最初几个小时内发生的关键分子事件，这些事件最终导致潜伏期间病毒发作的稳定维持。具体来说，我们将定义在B细胞潜伏期建立阶段发生的病毒转录和基因组事件（目的1），我们将定义建立稳定潜伏期所需的特定晚期裂解基因（目的2），我们将验证关键裂解基因诱导表观遗传修饰的假设，这对B细胞潜伏期的建立至关重要。拟议的研究应提供重要的新见解，发生在B细胞γ疱疹病毒感染的最早时刻的关键分子事件。

DESCRIPTION (provided by applicant): Human gammaherpesvirus infection is linked to the development of multiple types of malignancies. These viruses pose a particularly significant risk to immunocompromised patients such as those infected with HIV. Gammaherpesviruses establish stable life-long latent infection in B cells, providing a lifelong reservoir of virus that can eventually contribute to the development of malignant disease. Our long-term goal is to define the mechanisms that gammaherpesviruses use to establish latency in B cells, thereby elucidating new targets for the development of modalities to prevent gammaherpesvirus-associated malignancies. Our approach is to dissect the earliest events of latency establishment using mutant viruses in the murine gammaherpesvirus (gammaHV68, MHV68) system that are unable to undergo lytic replication. By comparing viruses that are mutated in early versus late lytic genes, we have uncovered a surprising role for lytic replication-associated gene products in the establishment of latency in B cells. We hypothesize that these key lytic gene products are critical for the induction of epigenetic modifications that are critical for retention of latent viral episomes. The goals of this proposal are to define the critical molecular events that occur in the earliest hours following B cell infection that ultimately result in stable maintenance of the viral episome during latency. Specifically, we will define the viral transcriptional and genomic events that occur during the establishment phase of B cell latency (Aim 1), we will define the specific late lytic gene that is required for the establishment of stable latency (Aim 2), and we will test the hypothesis that the crucial lytic gene induces epigenetic modifications that are critical for latency establishment in B cells. The proposed studies should provide significant new insight into the critical molecular events that occur during the earliest moments of gammaherpesvirus infection of B cells. PUBLIC HEALTH RELEVANCE: Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus infections are linked to the development of numerous types of cancers, and pose a particularly significant risk to AIDS patients and transplant recipients. The proposed research will examine the events that occur in the earliest stages of infection in an effort to gain new insight into the means by which these viruses establish lifelong infections. This work has important implications for the development of drugs to prevent or treat virus-associated cancers.