Global splicing pattern reversion during somatic cell reprogramming.

Alternative splicing generates multiple transcripts from a single gene, and cell-type-specific splicing profiles are important for the properties and functions of the cells. Recently, somatic cells have been shown to undergo dedifferentiation after the forced expression of transcription factors. However, it remains unclear whether somatic cell splicing is reorganized during reprogramming. Here, by combining deep sequencing with high-throughput absolute qRT-PCR, we show that somatic splicing profiles revert to pluripotent ones during reprogramming. Remarkably, the splicing pattern in pluripotent stem cells resembles that in testes, and the regulatory regions have specific characteristics in length and sequence. Furthermore, our siRNA screen has identified RNA-binding proteins that regulate splicing events in iPSCs. We have then demonstrated that two of the RNA-binding proteins, U2af1 and Srsf3, play a role in somatic cell reprogramming. Our results indicate that the drastic alteration in splicing represents part of the molecular network involved in the reprogramming process.