REGULATION OF SV40 LATE GENE EXPRESSION

默茨博士研究计划的长期目标 实验室将通过以下方式在分子水平上了解这些机制 SV40晚期基因的哪些表达受调控及其调控途径 病毒编码的癌蛋白，大T抗原，会影响表达 这些基因和其他基因。在建议的授权期内，Mertz 研究小组将继续研究，旨在了解几个 这项规定的各个方面。具体来说，他们将：(1)确定 SV40主要晚期启动子的转录启动机制 (SV40-MLP)通过以下方式：(A)检验 TFIID与TFIID-30区功能结合的机制 启动子，(B)进一步表征和确定 IAP/DAP和IBP，结合遗传重要性的细胞蛋白 SV40-MLP的起始点和下游序列元件，(C) 测试假设的有效性，即发起者元素只是 RNA聚合酶II首选的序列作为 转录，以及(D)开始鉴定和确定 参与转录启动的细胞蛋白的功能 在具有确定的体外转录系统的SV40-MLP上；以及(2) 确定SV40大T抗原调节SV40的机制 通过(A)鉴定顺式作用序列元件的晚期基因表达 SV40-MLP的转录反式激活机制 大T抗原可以被介导，(B)确定是否直接， SV40之间存在遗传上重要的蛋白质-蛋白质相互作用 大T抗原与参与转录的细胞蛋白 在SV40-MLP上启动，(C)鉴定细胞蛋白 参与SV40-MLP的转录启动，其特异性 SV40大T抗原间接改变活性，并开始 以确定其中一种变化发生的机制，以及 (D)开始确定SV40大T抗原后如何- 转录反式激活SV40晚期基因的表达。 这些研究应该有助于了解肿瘤 抗原可以改变基因表达，有时可能导致 细胞向致癌状态的转化和增加 对真核细胞所使用的一些机制的理解 调控基因表达。

The long-term objectives of the research program in Dr. Mertz's laboratory are to understand at the molecular level the mechanisms by which expression of the late genes of SV40 are regulated and the ways in which the virus-encoded oncoprotein, large T antigen, affects expression of these and other genes. During the proposed grant period, the Mertz research group will continue studies aimed at understanding several aspects of this regulation. specifically, they will: (1) determine the mechanism of transcription initiation at the SV40 major late promoter (SV40-MLP) by (a) testing the validity of the "context hypothesis" for the mechanism of functional binding of TFIID to the -30 region of this promoter, (b) further characterizing and determining the functions of IAP/DAP and IBP, cellular proteins that bind the genetically important initiation site and downstream sequence elements of the SV40-MLP, (c) testing the validity of the hypothesis that initiator elements are simply sequences preferred by RNA polymerase II as start sites for transcription, and (d) beginning identification and determination of the functions of the cellular proteins involved in transcription initiation at the SV40-MLP with a defined in vitro transcription system; and (2) determine the mechanisms by which SV40 large T antigen modulates SV40 late gene expression by (a) identifying the cis-acting sequence elements of the SV40-MLP through which transcriptional transactivation by SV40 large T antigen may be mediated, (b) determining whether direct, genetically important protein-protein interactions occur between SV40 large T antigen and the cellular proteins involved in transcription initiation at the SV40-MLP, (c) identifying the cellular proteins involved in transcription initiation at the SV40-MLP whose specific activities are altered indirectly by SV40 large T antigen, and beginning to determine the mechanism by which one of these alterations occurs, and (d) beginning to determine how SV40 large T antigen post- transcriptionally transactivates expression f the late genes of SV40. These studies should help both to learn about mechanisms by which tumor antigens can alter gene expression in ways that may on occasion lead to the transformation of cells to an oncogenic state and to increase understanding of some of the mechanisms used by eukaryotic cells in regulating gene expression.