REGULATION OF MESSENGER RNA SPLICING

在转录后水平上控制基因表达是一种 生物学中与癌症相关的基本问题。这个 调节细胞和细胞的选择性剪接的机制 病毒基因将被研究，重点是全球机制， 对不同组织中大组前-mRNAs表达的影响 组织、发育阶段和/或对外部信号的反应。 三个人类选择性剪接因子家族将是 调查：(I)SF7因素，以最近的 鉴定的SF7A蛋白；(Ii)hnRNP A/B蛋白，其中 最具特征的是hnRNP A1；和(Iii)SR蛋白，其 样机为SF2/ASF。SR蛋白的功能也是结构性的 拼接因子，但这个项目将重点放在它们的能力上 在体内和体外以一定浓度调制选择性剪接- 依赖的态度。此活动被hnRNP A/B拮抗 调节选择性5‘剪接位点选择的蛋白质，以及通过SF7 确定备选3‘剪接位点选择的蛋白质。这个 这些个体成员的分子机制 调节选择性剪接位点的RNA结合蛋白家族 选择，以及它们如何实现底物专一性，将继续 利用生化、分子和反向遗传学进行研究 接近了。此外，具体的成对假设 这些拮抗因素的组合被用来调节 将测试特定组前mRNA的替代剪接，以及 建议进行实验以识别自然的、特定的前mRNA 这些蛋白质中的每一种在体内都是调控的靶点。这些 研究与该计划的总体目标直接相关 项目。作为替代前mRNA剪接的全球监管机构， SR、hnRNP A/B和SF7蛋白是很好的候选蛋白 解释了观察到的mRNA表达的异常模式 转化细胞中的大量基因。在潜在的目标中 这些调节子是几个关键基因，参与了 建立或维持转化的表型，或在 恶性进展。对选择性剪接的调节是 负责产生致癌和非致病形式的 许多细胞癌基因和病毒癌基因。因此，教唆者 对选择性剪接的基本机制的理解 监管，以及这一过程的特殊性，可能导致 从长远来看，到识别特定影响 特定蛋白质异构体的合成，这些蛋白质在 肿瘤发生学。

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.