PROCESSING OF PREMESSENGER RNA

本提案中的实验旨在研究 后生动物剪接位点和外显子组成性地 并且在前体mRNA剪接期间被替代地识别。 除了 剪接位点、外显子/内含子长度和序列是重要参数 用于外显子识别。 该方案研究了6个弱外显子或内含子 需要特殊的序列来促进或调节它们的 识别. 三个研究的元素是外显子，三个是 内含子的 描述了实验以识别和表征 这些因素参与了早期对这些元素的认识， 剪接体的组装。 研究的内容包括： 心肌肌钙蛋白T和钙调蛋白基因的多重外显子增强子 基因，可以增强包含大的内部外显子和调节 侧翼5 ′剪接位点的使用。 来自HIV的多部分外显子沉默子抑制上游的使用 3'剪接位点。 来自心肌肌钙蛋白T的重复简单序列内含子增强子， 补偿了相邻组成型外显子的小尺寸。 来自α珠蛋白的富含G的内含子增强子，其促进剪接和 调节5 ′剪接位点的使用。 果蝇第一小内含子中的一个富含C的内含子序列 识别5'和3'剪接位点所需的无雄性基因。

The experiments in this proposal are aimed at investigating the mechanisms whereby metazoan splice sites and exons are constitutively and alternatively recognized during pre-mRNA splicing. In addition to splice sites, exon/intron length and sequence are important parameters for exon recognition. This proposal studies six weak exons or introns that require special sequences to facilitate or regulate their recognition. Three of the studied elements are exonic, three are intronic. Experiments are described to identify and characterize the factors that participate in recognition of these elements during early assembly of the spliceosome. The elements under the study include: Multi-partite exon enhancers from the cardiac troponin T and caldesmon genes that can enhance inclusion of large internal exons and regulate usage of flanking 5' splice sites. Multi-partite exon silencer from HIV that depresses usage of upstream 3' splice sites. Duplicated simple-sequence intron enhancer from cardiac troponin T that compensates for the small size of an adjacent constitutive exon. A G-rich intron enhancer from alpha globin that facilitates splicing and regulates usage of 5' splice sites. A C-rich intron sequence from the small first intron of the Drosophila maleless gene required for recognition of the 5' and 3' splice sites.