REGULATION OF MESSENGER RNA SPLICING

在转录后水平上对基因表达的控制是一个重要的机制。 生物学中的基本问题，与癌症有关。 的 调节细胞的选择性剪接的机制， 病毒基因将被调查，重点是全球机制， 影响不同细胞中大量前体mRNA的表达， 组织、发育阶段和/或响应于外部信号。 三个家族的人类可变剪接因子将被 调查：（一）SF 7因素，以最近的 鉴定的SF 7 A蛋白;（ii）hnRNP A/B蛋白，其中 最好表征的是hnRNP A1;和（iii）SR蛋白，其 原型是SF 2/ASF。 SR蛋白也作为组成型蛋白发挥功能。 剪接因子，但这个项目将集中在他们的能力， 在体内和体外调节可变剪接， 依赖的方式。 该活性被hnRNP A/B拮抗 调节可变5'剪接位点选择的蛋白质，以及通过SF 7 蛋白质以确定选择性3'剪接位点选择。的 分子机制，通过这些分子机制， RNA结合蛋白家族调节可变剪接位点 选择，以及它们如何实现底物特异性，将继续 利用生物化学、分子学和反向遗传学 接近。 此外，假设特定的成对 这些拮抗因子的组合用于调节 将检测特定前mRNA组的选择性剪接， 实验提出了确定天然的，特定的前mRNA 这些蛋白在体内的调节靶点。这些 研究与该计划的总体目标直接相关 项目 作为替代性前mRNA剪接的全球调节剂， SR、hnRNP A/B和SF 7蛋白是与细胞凋亡相关的 解释了观察到的mRNA表达的异常模式， 转化细胞中的许多基因。在潜在的目标中， 这些调节因子是几个关键基因， 转化表型的建立或维持，或在 恶性肿瘤的进展。 选择性剪接的调节是 负责产生致癌和非致癌形式的 许多细胞和病毒癌基因。 因此，教唆者 理解选择性剪接的基本机制 监管，以及这一过程的特异性，可能会导致，在 从长远来看，以确定药物，具体影响 合成特定的蛋白质异构体， 肿瘤发生

The control of gene expression at the post-transcriptional level is a fundamental problem in biology, with relevance to cancer. The mechanisms for the regulation of alternative splicing of cellular and viral genes will be investigated, focusing on global mechanisms that affect the expression of large sets of pre -mRNAs in different tissues, developmental stages, and/or in response to external signals. Three families of human alternative splicing factors will be investigated: (I) the SF7 factors, exemplified by the recently identified SF7A protein; (ii) the hnRNP A/B proteins, of which the best characterized is hnRNP A1; and (iii) the SR proteins, whose prototype is SF2/ASF. The SR proteins function also as constitutive splicing factors, but this project will focus on their ability to modulate alternative splicing in vivo and in vitro in a concentration- dependent manner. This activity is antagonized by hnRNP A/B proteins to modulate alternative 5' splice site selection, and by SF7 proteins to determine alternative 3' splice site selection. The molecular mechanisms by which individual members of these families of RNA-binding proteins modulate alternative splice site selection, and how they achieve substrate specificity, will continue to be studies using biochemical, molecular, and reverse genetic approaches. In addition, the hypothesis that specific pairwise combinations of these antagonistic factors are used to regulate alternative splicing of specific sets of pre-mRNAs will be tested, and experiments are proposed to identify natural, specific pre-mRNA targets for regulations by each of these proteins in vivo. These studies are directly relevant to the overall goals of the program project. As global regulators of alternative pre-mRNA splicing, the SR, hnRNP A/B, and SF7 proteins are excellent candidates to account for the observed aberrant patterns of mRNA expression of numerous genes in transformed cells. Among potential targets of these regulators are several critical genes involved in the establishment or maintenance of the transformed phenotype, or in progression of malignancy. Regulation of alternative splicing is responsible for generating oncongenic and non-oncognic forms of many cellular and viral oncogenes. Therefore, a abetter understanding of the basic mechanisms of alternative splicing regulation, and of the specificity of this process, may lead, in the long term, to the identification of drugs that specifically affect the synthesis of particular protein isoforms that play critical roles in tumorigenesis.