SRSF10 regulates alternative splicing and is required for adipocyte differentiation.

During adipocyte differentiation, significant alternative splicing changes occur in association with the adipogenic process. However, little is known about roles played by splicing factors in this process. We observed that mice deficient for the splicing factor SRSF10 exhibit severely impaired development of subcutaneous white adipose tissue (WAT) as a result of defects in adipogenic differentiation. To identify splicing events responsible for this, transcriptome sequencing (RNA-seq) analysis was performed using embryonic fibroblast cells. Several SRSF10-affected splicing events that are implicated in adipogenesis have been identified. Notably, lipin1, known as an important regulator during adipogenesis, was further investigated. While lipin1β is mainly involved in lipogenesis, its alternatively spliced isoform lipin1α, generated through the skipping of exon 7, is primarily required for initial adipocyte differentiation. Skipping of exon 7 is controlled by an SRSF10-regulated cis element located in the constitutive exon 8. The activity of this element depends on the binding of SRSF10 and correlates with the relative abundance of lipin1α mRNA. A series of experiments demonstrated that SRSF10 controls the production of lipin1α and thus promotes adipocyte differentiation. Indeed, lipin1α expression could rescue SRSF10-mediated adipogenic defects. Taken together, our results identify SRSF10 as an essential regulator for adipocyte differentiation and also provide new insights into splicing control by SRSF10 in lipin1 pre-mRNA splicing.