Regulation and Function of Human Polyomavirus circular RNAs

已经发现越来越多的环状RNA（circRNA）由病毒和病毒载体表达。 虽然在病毒感染期间，人类宿主细胞中的circRNA的表达水平很低，但大多数circRNA的生理意义仍不清楚。 我们的长期目标是利用人类多瘤病毒（HPyVs）来了解 circRNA，并利用这些知识开发新的诊断和治疗病毒感染的方法。 疾病我们认为，许多病毒circRNA作为编码RNA发挥作用，这些编码RNA具有与 从同一基因拼接的线性RNA。具体来说，我们的中心假设是默克尔细胞 多瘤病毒和棘突发育不良多瘤病毒编码环状ALTO RNA， 被翻译成ALTO，然后ALTO调节受感染的宿主细胞中的转录。该模型是基于 初步研究表明，MCPyV和TSPyV早期区域都有效地产生circALTO， 在体外被翻译成ALTO蛋白。MCPyV circALTO作为转录反式激活因子发挥作用， 可以诱导先前与DNA有关的多个基因和途径的转录 病毒感染。我们进一步证明了从MCPyV早期区域表达的miRNA，miR-M1， 负调节circALTO和ALTO水平。扩展和验证此模型将代表 这是我们对circRNA功能和调控的理解的突破性进展。这项提案将是 分为两个目标：1）确定调节MCPyV circALTO形成的因素及其作用机制。 MCPyV miR-M1 miRNA的抑制作用，并确定这些因素如何影响病毒复制， 2）确定MCPyV ALTO如何调节宿主细胞转录以及ALTO的作用是否 在转录上是保守的。我们将与病毒学家合作， 多瘤病毒和miRNA生物学来完成所提出的目标。完成本提案将不会 这不仅扩大了circRNA在病毒学和细胞信号传导中的相关性，而且还大大提高了我们的研究水平。 了解人类多瘤病毒的发病机制。

An increasing number of circular RNAs (circRNAs) have been found to be expressed by both viruses and human host cells during viral infection, yet the physiological significance of most circRNAs remains unclear. Our long-term goal is to use human polyomaviruses (HPyVs) to understand the regulation and function of circRNAs and to leverage this knowledge towards developing new diagnostics and treatments for viral diseases. We propose that many viral circRNAs function as coding RNAs that have distinct properties from linear RNAs spliced from the same gene. Specifically, our central hypothesis is that Merkel cell polyomavirus and trichodysplasia spinulosa polyomavirus encodes circular ALTO RNAs, circALTOs, that are translated to ALTO, which then modulates transcription in infected host cells. This model is based on preliminary studies showing that both MCPyV and TSPyV early regions efficiently generate circALTO, which are translated into ALTO protein in vitro. MCPyV circALTO functions as a transcriptional transactivator that can induce the transcription of multiple genes and pathways that have previously been implicated in DNA virus infections. We further demonstrate that a miRNA expressed from the MCPyV early region, miR-M1, negatively regulates circALTO and ALTO levels. Extending and validating this model would represent a ground-breaking advance in our understanding of circRNA function and regulation. This proposal will be organized into two aims: 1) Identify the factors that regulate the formation of MCPyV circALTO and its inhibition by the MCPyV miR-M1 miRNA and determine how these factors impact viral replication and persistence; 2) Determine how MCPyV ALTO modulates host cell transcription and whether ALTO’s effects on transcription are conserved in TSPyV. We will collaborate with virologists with expertise in polyomaviruses and miRNA biology to complete the proposed aims. Completion of this proposal will not only expand the relevance of circRNAs in virology and cell signaling but also significantly advance our understanding of the pathogenesis of human polyomaviruses.