Regulation of mammalian mRNA splicing by CA repeat enhancer elements

哺乳动物mRNA剪接通常通过影响剪接效率和选择性剪接位点的使用的RNA剪接增强子来调节。剪接增强子通常位于外显子中，通常由富含嘌呤或CA的序列组成，并通过结合调节蛋白因子发挥功能。该项目的重点是人类内皮型一氧化氮合酶（e-NOS）基因，该基因在血管稳态中起关键作用，并被认为是动脉粥样硬化和心血管疾病的决定因素。在内含子13中存在多态性CA重复区域，最近发现CA重复的数量与冠状动脉疾病的风险之间存在相关性。在初步工作中，我们已经确定了内含子13中的CA重复区域是一个不寻常的剪接增强子元件，其活性取决于CA重复数。该项目的具体目标是表征CA重复区域作为剪接调控元件的作用机制，包括其与蛋白质和一般剪接机制的相互作用，并评估其在选择性剪接中的功能意义。此外，这些发现将扩展到其他含有CA重复序列的人类基因。

Mammalian mRNA splicing is often regulated through RNA splicing enhancers that influence splicing efficiency and the use of alternative splice sites. Splicing enhancers usually reside in exons, often consist of purine- or CA-rich sequences, and function through binding of regulatory protein factors. This project focuses on the human gene for endothelial nitric oxide synthase (e-NOS), which plays a key role in vascular homeostasis and has been implicated as a determinant of atherosclerosis and cardiovascular diseases. There is a polymorphic CA repeat region in intron 13, for which a correlation between the number of CA repeats and the risk for coronary artery disease has been recently discovered. In preliminary work we have identified this CA repeat region in intron 13 as an unusual splicing enhancer element, the activity of which depends on the CA repeat number. Specific aims of this project are to characterize the mechanism of action of the CA repeat region as a splicing-regulatory element, including its interactions with proteins and the general splicing machinery, and to assess its functional significance in alternative splicing. In addition, these findings will be extended to other CA repeat-containing human genes.