Transcriptome processing networks in skeletal muscle: mechanisms and functions

描述(申请人提供)：除了基因输出的转录调控外，哺乳动物基因组还通过选择性剪接和在前信使核糖核酸加工过程中选择替代的3‘信使核糖核酸末端来产生广泛的转录组和蛋白质组多样性。至于转录，转录组的处理受到广泛的调节，以响应动态的生理需求。转录组加工的调控涉及由RNA结合蛋白控制的相互连接的网络，这些RNA结合蛋白与调控加工位点附近的前mRNA中的首选序列基序结合。该项目的长期目标是确定成人骨骼肌转录组处理的范围、调节机制和功能后果。转录组处理网络的破坏导致骨骼肌疾病，但对正常调节的程度或功能知之甚少。在这项建议的第一部分，我们将确定骨骼肌中由Fox RNA结合蛋白家族控制的调控网络，并确定它们在成肌细胞分化过程中的功能。我们将使用在骨骼肌中表达的两个Fox基因的组织特异性和诱导性敲除来确定成年骨骼肌中肌纤维和卫星细胞中的调控网络的功能。在提案的第二部分，我们将在高通量RNAi屏幕上使用双色剪接报告确定在成肌细胞分化过程中起作用的额外调控网络。所获得的知识将被用于理解这些网络在成人骨骼肌中的作用。这一结果将对核转录后调控在成人骨骼肌不同的稳态功能及其修复能力中的作用提供新的理解。这一认识对于开发和应用新的治疗策略来治疗对骨骼肌功能产生负面影响的疾病非常重要。

DESCRIPTION (provided by applicant): In addition to transcriptional regulation of gene output, mammalian genomes produce extensive transcriptome and proteome diversity by alternative splicing and selection of alternative 3' mRNA ends during pre-mRNA processing. As for transcription, transcriptome processing is extensively regulated in response to dynamic physiological needs. The regulation of transcriptome processing involves interconnected networks controlled by RNA binding proteins that bind to preferred sequence motifs within the pre-mRNA near the sites of regulated processing. The long term goal of this project is to determine the extent, regulatory mechanisms, and functional consequences of transcriptome processing in adult skeletal muscle. The disruption of transcriptome processing networks contributes to disease in skeletal muscle yet little is known regarding the extent or functions of normal regulation. In the first part of this proposal, we will identify the regulatory networks controlled by the Fox family of RNA binding proteins in skeletal muscle and determine their functions during myoblast differentiation. We will use tissue specific and inducible knock outs of the two Fox genes expressed in skeletal muscle to determine the functions of the regulatory networks in myofibers and satellite cells in adult skeletal muscle. In the second part of the proposal, we will identify additional regulatory networks operative during myoblast differentiation using a bichromatic splicing reporter in high throughput RNAi screens. Knowledge gained will be directed toward understanding the roles of these networks in adult skeletal muscle. The results will provide a new understanding of the role of nuclear post-transcriptional regulation in the diverse homeostatic functions of adult skeletal muscle and its capacity for repair. This understanding is important for development and application of novel therapeutic strategies to conditions that negatively affect skeletal muscle function.