MyoD作为骨骼肌中特异表达的转录因子，在细胞命运决定及细胞分化过程中发挥重要作用，然而MyoD精确而特异的调控靶基因的详细分子机制还不清楚。申请人前期鉴定了一个骨骼肌特异表达的长非编码RNA-linc-RAM, 发现它可与MyoD结合并影响其调控靶基因的特异性。然而linc-RAM影响表达的882个基因中，只有151基因受MyoD调控，提示除linc-RAM外体内还存在其他机制参与MyoD的特异性决定。为探究RNA结合蛋白（RNA binding protein, RBPs）是否参与MyoD特异性调控，我们计划利用CRISPR-RBP文库进行系统筛选和验证，并针对筛选出的RBPs构建条件性敲除小鼠，解析RBPs在MyoD介导的肌细胞谱系基因表达和细胞分化的功能和机制。该项目的完成不仅是探索MyoD特异性决定机制方面的理论新突破，而且将为临床上某些骨骼肌疾病寻找新的药物或防治提供理论依据。

As a specific-expressed transcription factor in skeletal muscle, MyoD plays important roles in cell-fate determination and differentiation. However, the precise mechanism about MyoD targeting in the genome is still unclear. The applicant previously identified a skeletal muscle specifically expressed long non-coding RNA, linc-RAM, and shown that it is able to bind MyoD and affect its specificity in the recognition of target genes. However, of the 882 genes affected by linc-RAM, only 151 genes were also regulated by MyoD, suggesting that there are other mechanisms involved in the target determination of MyoD. In order to investigate whether RNA binding proteins (RPBs) are involved in MyoD-specific regulation, we are planning to perform CRISPR screening with a RBP library to search potential RBP regulators. With the screened candidates, we will construct conditional knockout mice and study the related functional mechanisms in MyoD mediated lineage determination and differentiation. The completion of this project is not only a theoretical breakthrough in the exploration of MyoD-specific determinants, but also lay the foundation for searching new drugs for the diagnosis and treatment of certain skeletal muscle diseases.