Deciphering the mechanism of the viral telomerase RNA in Marek’s disease virus pathogenesis and tumorigenesis

马立克氏病病毒（MDV）是一种高度致癌的α疱疹病毒，可导致鸡的致命性T细胞淋巴瘤。MDV编码的端粒酶RNA（vTR）在MDV诱导的肿瘤形成中起着至关重要的作用。它与鸡的细胞TR（cTR）有88%的序列同一性，并促进端粒酶活性。我们以前证明了vTR的促肿瘤功能独立于其在端粒酶复合物中的作用。此外，我们发现vTR与细胞蛋白RpL 22相互作用并重新定位，RpL 22是T细胞发育和转化的重要因素。到目前为止，这种vTR-RpL 22相互作用在MDV诱导的肿瘤形成中的作用仍然难以捉摸。此外，我们提供了初步的数据，vTR有额外的相互作用的合作伙伴，并具有抗凋亡功能。考虑到这些方面，我们假设vTR与RpL 22和/或其他相互作用伴侣的相互作用以及vTR介导的细胞凋亡抑制有助于肿瘤形成。我们将在三个具体目标中讨论这一假设。具体而言，我们将1）破译vTR-RpL 22相互作用在MDV诱导的肿瘤发生中的作用，2）鉴定新的vTR相互作用伴侣并确定它们是否有助于肿瘤细胞增殖，以及3）研究允许vTR抑制细胞凋亡的机制。为了解决目标1，我们将突变vTR中的RpL 22-共有结合位点，并评估这些vTR突变体与RpL 22相互作用和重新定位RpL 22的能力。此外，我们将产生携带这些突变的重组病毒，以确定vTR-RpL 22相互作用是否在MDV诱导的肿瘤发生中起作用。为了实现目标2，我们将进行RNA-蛋白质沉淀试验，并通过质谱法鉴定新的相互作用伴侣。我们将评估vTR是否影响这些新的相互作用伴侣的定位，以及它们是否有助于MDV诱导的肿瘤细胞增殖。在目标3中，我们将进一步研究vTR的抗凋亡特性，并评估它是否依赖于端粒酶复合物。此外，我们将确定vTR是否在病毒进化过程中获得了这种功能，或者细胞同源物cTR是否已经具有这种活性。该提案将定义vTR及其在MDV诱导的肿瘤发生中的相互作用伙伴的分子机制，提供对这种致命病原体的发病机制的更深入理解。

Marek’s disease virus (MDV) is a highly oncogenic alphaherpesvirus that causes deadly T cell lymphoma in chickens. MDV encodes a telomerase RNA (vTR) that plays a crucial role in MDV-induced tumor formation. It shares an 88% sequence identity with the cellular TR in chickens (cTR) and promotes telomerase activity. We previously demonstrated that the tumor-promoting functions of vTR act independent of its role in the telomerase complex. Furthermore, we showed that vTR interacts with and re-localizes the cellular protein RpL22, which is an important factor in T-cell development and transformation. Until now, the role of this vTR-RpL22 interaction in MDV-induced tumor formation remains elusive. In addition, we provide preliminary data that vTR has additional interaction partners and possesses anti-apoptotic functions. Considering these aspects, we hypothesize that the interaction of vTR with RpL22 and/or other interaction partners as well as vTR-mediated inhibition of apoptosis contribute to tumor formation. We will address this hypothesis in three specific aims. Specifically, we will 1) decipher the role of the vTR-RpL22 interaction in MDV-induced tumorigenesis, 2) identify novel vTR interaction partners and determine if they contribute to tumor cell proliferation, and 3) investigate the mechanism that allows vTR to inhibit apoptosis. To address aim 1, we will mutate the RpL22-consensus binding sites in vTR and assess the ability of these vTR mutants to interact with and re-localize RpL22. In addition, we will generate recombinant viruses harboring these mutations to determine if the vTR-RpL22 interaction plays a role in MDV-induced tumorigenesis. To achieve aim 2, we will perform RNA-Protein precipitation assays and identify novel interaction partners by mass spectrometry. We will assess if vTR affects the localization of these novel interaction partners and if they contribute to MDV-induced tumor cell proliferation. In aim 3, we will further investigate the anti-apoptotic properties of vTR and assess if it is dependent on the telomerase complex. In addition, we will determine if vTR acquired this function during virus evolution or if the cellular homologue cTR already possesses this activity. This proposal will define the molecular mechanism(s) of vTR and its interaction partners in MDV-induced tumorigenesis, providing a deeper understanding of the pathogenesis of this deadly pathogen.