Molecular Characterization of Herpes Simplex Virus ICP27

单纯疱疹病毒 ICP27 的分子表征

• 批准号: 7982880
• 负责人: STEPHEN A RICE
• 金额: $ 30.2万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7982880
• 关键词: Binding; Biological Models; Biology; Blindness; Cell Nucleus; Cell physiology; Cells; Cis-Acting Sequence; Complex; Cytoplasm; Encephalitis; Exons; Gene Expression; Gene Silencing; Gene Targeting; Genes; Genome; Goals; HSV glycoprotein C; Herpesviridae; Herpesviridae Infections; Herpesvirus 1; Human; Human Herpesvirus 2; Human Virus; Immediate-Early Proteins; Infection; Introns; Keratitis; Lead; Messenger RNA; MicroRNAs; Modality; Modeling; Molecular; Names; Neurons; Newborn Infant; Nuclear; Nuclear Export; Outcome; Pathway interactions; Play; Production; Proteins; RNA Processing; RNA Splicing; Research; Role; Signal Transduction; Simplexvirus; System; Testing; Therapeutic; Transcript; Transcriptional Silencer Elements; Variant; Viral; Viral Genes; Viral Proteins; Viral Regulatory Proteins; Virus Latency; Virus Replication; Work; base; innovation; latency associated transcript; latent infection; mRNA Export; mRNA Precursor; mRNA Stability; mRNA Transcript Degradation; novel; novel strategies; nuclease; pathogen; prevent; public health relevance; research study; response

DESCRIPTION (provided by applicant): HSV-1 is a widespread human pathogen. In addition, it serves as an important model to study how pathogenic human herpesviruses regulate their genes during infections. One protein that is critical for HSV-1 gene expression is the immediate-early protein ICP27. In this application, we propose to study two distinct functions of ICP27 that regulate viral gene expression. In Specific Aim 1, we will study how ICP27 stimulates mRNA accumulation from delayed-early (DE) and late (L) target genes. The current leading model for how ICP27 turns on viral genes is that it functions as a mRNA export factor that transports intronless viral transcripts to the cytoplasm. However, this model cannot readily explain how ICP27 dramatically promotes the accumulation of certain viral mRNAs, including that encoding glycoprotein C (gC). Our recent work on the gC gene suggests a novel model in which ICP27 prevents newly transcribed but inherently unstable viral transcripts from being rapidly degraded in the nucleus by a host cell nuclease. This nuclease targets the gC mRNA in response to a specific cis-acting sequence in the body of the message. We have named this sequence the silencing element (SE). Intriguingly, the SE can be transferred to another gene, where it functions both to silence the gene as well as to confer ICP27-dependent expression. In this Aim, we will study how the SE and ICP27 functionally interact to regulate mRNA stability. We will also study how ICP27 regulates other viral genes DE and L genes, as well as the gene for the viral latency-associated transcript (LAT), which we have recently shown is regulated by ICP27 at the level of mRNA stability. In Specific Aim 2, we will study how ICP27 promotes the retention of introns in viral mRNAs. This Aim is based on our recent discovery that the gC gene contains a functional intron, the retention of which is enhanced by ICP27. The spliced transcript encodes a secreted variant of gC, called gCsec. It is not known how ICP27 promotes the retention of introns in mature mRNA. However, very few cellular or viral regulators of intron-retention have been identified, so ICP27 serves as a valuable model to understand how this important cellular process can be regulated. Three models are proposed to explain how ICP27 regulates intron-retention, and experiments are outlined to test these. The second part of this Aim seeks to identify novel introns in the HSV-1 genome that are regulated by ICP27. Viral genes harboring such introns may encode biologically important protein variants, analogous to gCsec. One such intron has already been identified in the UL24 gene, which encodes a protein important for neuronal replication. Together, our studies will illuminate how an essential but poorly understood viral regulatory protein controls the fate of viral mRNAs, and in so doing, helps determine the outcome of HSV-1 infections.

描述（由申请人提供）：HSV-1是一种广泛的人类病原体。此外，它是研究致病性人疱疹病毒在感染过程中如何调节其基因的重要模型。对HSV-1基因表达至关重要的一种蛋白质是直接至上的蛋白质ICP27。在此应用中，我们建议研究调节病毒基因表达的ICP27的两个不同功能。在特定目标1中，我们将研究ICP27如何刺激延迟（DE）和晚（L）靶基因的mRNA积累。 ICP27如何打开病毒基因的当前领先模型是，它是将无内在病毒转录物传输到细胞质的mRNA输出因子。但是，该模型无法轻易解释ICP27如何显着促进某些病毒mRNA的积累，包括编码糖蛋白C（GC）。我们最近在GC基因上的工作提出了一个新型模型，其中ICP27防止了新转录但固有的不稳定病毒转录本无法通过宿主细胞核酸酶快速降解在细胞核中。该核酸酶靶向GC mRNA，以响应消息体内的特定顺式作用序列。我们将此序列命名为沉默元素（SE）。有趣的是，可以将SE转移到另一个基因上，在该基因中，它既可以使基因沉默，又可以赋予ICP27依赖性表达。在此目标中，我们将研究SE和ICP27如何在功能上相互作用以调节mRNA稳定性。我们还将研究ICP27如何调节其他病毒基因DE和L基因，以及与病毒潜伏相关的转录本（LAT）的基因（我们最近显示的）在mRNA稳定水平下受到ICP27的调节。在特定目标2中，我们将研究ICP27如何促进病毒mRNA中内含子的保留。这个目的是基于我们最近发现的GC基因包含功能内含子，ICP27增强了功能内含子。剪接的转录本编码GC的分泌变体，称为GCSEC。尚不清楚ICP27如何促进内含子在成熟mRNA中的保留。但是，已经鉴定出很少有内含子滞留的细胞或病毒调节剂，因此ICP27是了解如何调节这一重要细胞过程的宝贵模型。提出了三种模型来解释ICP27如何调节内加保留的方式，并概述了测试这些模型。该目标的第二部分旨在鉴定由ICP27调节的HSV-1基因组中的新内含子。带有这种内含子的病毒基因可以编码类似于GCSEC的生物学上重要的蛋白质变异。在UL24基因中已经确定了这样的内含子，该基因编码了一种对神经元复制重要的蛋白质。总之，我们的研究将阐明基本但鲜为人知的病毒调节蛋白如何控制病毒mRNA的命运，并有助于确定HSV-1感染的结果。