Histone variant H3.3 and KSHV LANA in the pathogenesis of oral Kaposi's sarcoma

描述（由申请人提供）： 卡波西肉瘤（KS）是人类免疫缺陷病毒（HIV）感染患者中最常见的口腔癌。卡波济肉瘤相关疱疹病毒（KSHV）是KS的病原体，也是两种淋巴组织增生性疾病：原发性渗出性淋巴瘤（PEL）和多中心Castleman病（MCD）。与艾滋病相关的KS在口腔中非常常见，口腔也是KSHV通过唾液脱落的主要部位。KSHV感染的肿瘤细胞主要是潜伏感染。病毒编码的潜伏相关核抗原（拉娜）是潜伏期所需的多功能蛋白。我们的初步数据表明，组蛋白变体H3.3，这是经常在人类恶性肿瘤中突变，并在转录调控中发挥重要作用，占据病毒附加体在特定区域，与拉娜结合。我们还表明，拉娜协会与Daxx和SSRP 1，伴侣蛋白负责沉积的H3.3。我们假设H3.3沉积到病毒游离体上对于潜伏期期间的病毒基因表达是至关重要的，并且此过程由拉娜与H3.3分子伴侣的相互作用介导。基因座特异性H3.3掺入可以解释潜伏期期间严格控制的基因表达模式，因此也影响潜伏性和裂解性复制之间的平衡，这可能对口腔中的肿瘤发生和脱落至关重要。重要的是，这项研究将不仅利用体外组织培养系统，但首次提出了一个高度创新的方法来分析复杂的染色质结构分析在体内使用初级口腔KS活检。为此，我们提供了初步的数据，我们的能力，检测内源性组蛋白H3.3的ChIP和IFA。这个跨学科试点项目的长期目标是创建概念数据证明，即调节组蛋白变体沉积可以作为一种新的KSHV特异性治疗策略。

DESCRIPTION (provided by applicant): Kaposi's sarcoma (KS) is the most common oral cancer in human immunodeficiency virus (HIV)-infected patients. Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of KS, and two lymphoproliferative diseases: primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). AIDS-associated KS is highly frequent in the oral cavity which is also the major site for KSHV shedding via saliva. KSHV infected tumor cells are predominately latently infected. The viral encoded latency-associated nuclear antigen (LANA) is a multifunctional protein required for latency. Our preliminary data demonstrate that histone variant H3.3, which is frequently mutated in human malignancies and plays important roles in transcriptional regulation, occupies viral episomes at specific regions that correlate with LANA binding. We also demonstrate that LANA associates with Daxx and SSRP1, chaperone proteins responsible for the deposition of H3.3. We hypothesize that H3.3 deposition onto viral episomes is crucial for viral gene expression during latency, and furthermore that this process is mediated by LANA's interactions with H3.3 chaperones. Locus specific H3.3 incorporation may account for the tightly controlled gene expression pattern during latency and hence also affect the balance between latent and lytic replication, which may be crucial with respect to tumorigenesis and shedding in the oral cavity. Importantly, this study will not only utilize in vitro tissue cultre systems but for the first time propose a highly innovative approach to analyze complex chromatin architecture analysis in vivo using primary oral KS biopsies. To this end we provide preliminary data on our ability to detect endogenous histone H3.3 by both ChIP and IFA. The long-term goal of this interdisciplinary pilot project is to create proof of concept data that modulating histone variant deposition can be harnessed as a novel KSHV-specific therapeutic strategy.