The Function And Mechanism Of Rbm24 During Embryonic Stem Cell Cardiac Differentiation And The Research On Rbm24-bound Transcripts

Despite the considerable advance in medicine and other methods,the incidence of heart failure is still high due to the irreversible myocardial necrosis.Embryonic stem cell(ESCs)derived cardiomyocytes provide a promising source for cell theropy and drug screening for heart disease.The transition of pluripotent ESCs to specific cardiomyocyte is accompanied with an expansion of mRNA and proteomic diversity.RNA binding proteins(RBPs)are key post-transcriptional regulators of tissue-specific splicing.Here,we showed that Rbm24 acts as a muscle-specific RBP,playing an essential role in ESC-cardiac differentiation via alternative splicing mechanism.We also illustrated that Rbm24 is a multi-tasking RNA binding protein by performing RNA-immunoprecipitation coupling with microarray(RIP-ChIP).Using an inducible mouse ESC line in which Rbm24 can be manipulated temporally,we found that Rbm24 can dramatically induce a cardiac-specific switch.RNA-sequencing uncovered more than 200 Rbm24-related alternative splicing events(AS)occurred during ESC differentiation,and these AS events remarkably focused on cardiac-specific development and functionality.By performing RIP-ChIP,we generated an atlas of Rbm24-bound mRNA repertoire.Further functional evaluation of its targets led to the elucidation of novel roles for Rbm24 in post-transcriptional processing,besides its already known roles in regulation of mRNA stability and alternative splicing:1.generation of isoforms with alternative transcriptional start sites,2.destabilization of Chrm2 via binding to an element in the coding region.This study provides a new insight of how an RNA binding protein influences ESC lineage differentiation by a splicing-mediated regulatory mechanism,and proposed a demonstration that Rbm24 is a multi-tasking RNA-binding protein capable of regulating its bound targets via a range of mechanisms.