Selective Degradation of mRNA by Herpes Simplex Virus 1

单纯疱疹病毒 1 对 mRNA 的选择性降解

• 批准号: 7984640
• 负责人: Bernard Roizman
• 金额: $ 33.54万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-10 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7984640
• 关键词: 3' Untranslated Regions; Actins; Applications Grants; Binding; Biology; Cells; Cleaved cell; Complex; Degradation Pathway; Elements; Endoribonucleases; Enzymes; FOS gene; Genes; Half-Life; Herpes Simplex Virus Protein Vmw65; Herpesvirus 1; Hour; Immune response; Infection; Ligands; Mediating; Messenger RNA; Modeling; Mus; Pancreatic ribonuclease; Pathogenesis; Perception; Poly(A)-Binding Proteins; Polyribosomes; Procedures; Protein Binding; Proteins; RNA; RNA Cap-Binding Proteins; Recruitment Activity; Relative (related person); Reporting; Research Proposals; Residual state; Ribonucleases; Role; Simplexvirus; Specificity; Stress; Structure; TIS11 protein; Testing; Time; Untranslated Regions; VP 16; Viral; Viral Proteins; Virion; Virus; base; biological adaptation to stress; decapping enzyme; eIF-4B; endoribonuclease; follow-up; mRNA Transcript Degradation; mutant; numb protein; protein function; public health relevance; research study; response; time interval

DESCRIPTION (provided by applicant): Virion host shutoff protein (VHS), the product of UL41 gene of herpes simplex virus 1(HSV-1) is the major viral suppressor of host responses to infection. VHS is brought into the infected cells by the virion and its primary function is to degrade mRNA. Our studies on VHS have completely revolutionized our understanding perceptions of the functions of the protein. Specifically: (i) We have developed a procedure for solubilization and purification of VHS to homogeneity. Purified VHS is an endoribonuclease that cleaves synthetic RNA with the specificity of RNase A in the absence of cellular or viral proteins. (ii) Earlier reports indicated that at mid and late times after infection VHS is "neutralized by the viral protein VP16. We showed that "neutralization" required the formation of a complex that includes VP22 in addition to VP16. (iii) Earlier reports indicated that the degradation of mRNA mediated by VHS is nonselective. We have identified and quantified the VHS- dependent degradation of 3 classes of mRNAs as follows: Class A consists of mRNAs that are normally stable (e.g. actin, GAPDH mRNAs, normal half life >12 h). In infected cells these mRNAs are degraded 5' to 3' within 30 minutes. Class B consists of stress response mRNAs (e.g. c-fos, cox-2, I:B1 and IEX-1 mRNAs) induced immediately after infection. These mRNAs contain AU-rich elements within their 3' UTRs. Typical half life of these mRNAs in mock infected cells is 30 to 45 min. Early after infection, these mRNAs are deadenylated and cleaved 5' to AU-rich elements. The residual portions linger with a half life >3 hrs. At late times (6+ h after infection) degradation of these mRNAs is dependent on ICP27. Both class A and class B mRNAs are degraded in polyribosomes. Class C includes mRNAs that are not degraded. The products of these mRNAs include tristetraprolin, a stress inducible protein that binds to AU-rich elements and sequesters the mRNAs to exosomes for 3' to 5' degradation and GADD452 a transcriptional factor. (iv) Earlier reports indicated that VHS binds 3 components of eIF4F complex, i.e. eIF4H, eIF4B and eIF4AII and VP16. Our studies have shown that VHS also interacts physically with tristetraprolin, ICP27, and through VP16 with VP22. The objective of the research proposal is to test a model of the degradation of the mRNAs in classes A and B. The model proposes that VHS degrades mRNAs in polyribosomes as reported, that it binds to a still to be defined component of eIF4F and mimics the function of the decapping enzymes by cleaving stable mRNAs downstream of the cap structure. The residual portion is then sequestered in P-bodies and rapidly degraded. In the case of class B mRNAs, VHS binds to tristetraprolin bound to AU-rich element mRNA and cleaves the mRNA 5' to the AU-rich elements. In the absence of bound tristetraprolin, the residual mRNA is not recruited promptly for degradation 3' to 5' by exosomes. We also propose to discriminate between 2 alternative potential functions of ICP27 in enabling mRNA degradation late in infection. Finally, given the multiple functions of VHS, the question arises as to the extent to which each function contributes to the pathogenic potential of HSV-1. PUBLIC HEALTH RELEVANCE: Cells respond vigorously to the entry of a virus into cells and Herpes simplex viruses evolved a complex strategy to block the cell from interfering with viral replication. One of the major suppressors of cellular responses is an enzyme brought into the cells by the virus that degrades mRNA made in response to infection. This grant application investigates the mechanisms by which this enzymes selectively degrades mRNA made in response to infection

描述（由申请人提供）：Virion宿主关闭蛋白（VHS），疱疹病毒1（HSV-1）的UL41基因的产物是宿主对感染的主要病毒抑制因子。 VHS被病毒座带入感染细胞中，其主要功能是降解mRNA。我们对VHS的研究完全彻底改变了我们对蛋白质功能的理解看法。具体而言：（i）我们已经开发了一种将VHS溶解和纯化为同质性的程序。纯化的VHS是一种内切核酸酶，在没有细胞或病毒蛋白的情况下将RNase A的特异性切割为RNase A的特异性。 （ii）较早的报告表明，在感染后的中期和晚期，VHS“被病毒蛋白VP16中和。我们表明，“中和”需要形成包括VP16的复合物，除了VP16外，还需要进行VP22。（iii）早期的报告表明，由VH介导的mRNA介导的MRNA介导了VHS的降级，并确定了vhsectional nistival-natiens forsective formentife formecled fornefiped fornefiped fornefiped fornefiped fornefiped fornefiped fornefiped fornefiped。如下：A类由通常稳定的mRNA组成（例如，肌动蛋白，GAPDH mRNA，正常的半寿命> 12 h。 3'utrs。 A类和B类mRNA均以多核糖体降解。 C类包括未降级的mRNA。这些mRNA的产物包括三烷酸蛋白，这是一种与富含Au的元素结合并将mRNA与外泌体隔离为3'至5'降解和GADD452的特性诱导蛋白和转录因子。 （iv）较早的报告表明，VHS结合了EIF4F复合物的3个组成部分，即EIF4H，EIF4B和EIF4AII和VP16。我们的研究表明，VHS还与Tristraprolin，ICP27以及通过VP22进行了物理相互作用。 The objective of the research proposal is to test a model of the degradation of the mRNAs in classes A and B. The model proposes that VHS degrades mRNAs in polyribosomes as reported, that it binds to a still to be defined component of eIF4F and mimics the function of the decapping enzymes by cleaving stable mRNAs downstream of the cap structure.然后将残留部分隔离为P体，并迅速退化。在B类mRNA的情况下，VHS与富含Au的元素mRNA结合的Tristraprolin结合，并将mRNA 5'切割至富含Au的元素。在没有结合的三坦酸蛋白的情况下，外泌体不会迅速募集残留的mRNA，以降级3“至5”。我们还建议区分ICP27的2种替代潜在功能，以使感染后期mRNA降解。最后，鉴于VHS的多个功能，出现了一个问题，即每个功能在多大程度上有助于HSV-1的致病潜力。 公共卫生相关性：细胞对病毒进入细胞的良好反应，单纯疱疹病毒进化了一种复杂的策略，以阻止细胞干扰病毒复制。细胞反应的主要抑制因子之一是病毒带入细胞中的酶，它会降解对感染的mRNA。该赠款申请研究了该酶选择性降解mRNA的机制