Role of the STAR proteins in early mammalian development [RNA-seq]

RNA binding proteins (RBPs), are emerging as important master regulators of the biology of stem cells in both pluripotency and differentiation. The Signal transduction and activation of RNA (STAR) is family of proteins shown to be involved in mammalian development. We characterized the role of two members of the family, Sam68 and Quaking (QKI), in pluripotency and differentiation of mouse embryonic stem cells (mESCs) by making use of CRISPR-Cas9 generated knock-out (KO) cell lines along with RNA-sequencing, ribosome profiling and RNA crosslinking followed by immunoprecipitation (iCLIP2). Our results indicate that both proteins are important in the regulation of mESCs cell cycle and self-renewal and are indispensable for proper cardiomyocyte differentiation by regulating expression, alternative splicing and translation of the cardiogenic factors GATA4. This work highlights the importance of the RBPs during the differentiation of mESCs.