Nuclear Accumulation of YTHDF1 Regulates mRNA Splicing in the DNA Damage Response
YTH domain-containing family protein 1 (YTHDF1), a reader of N6-methyladenosine, has been implicated in regulating RNA metabolism in the cytosol. Here we report a role of YTHDF1 within the nucleus in response to genotoxic stress. Upon radiation, YTHDF1 is phosphorylated at serine 182 in an ATR-dependent manner. This phosphorylation inhibits exportin 1-mediated nuclear export of YTHDF1, resulting in its accumulation within the nucleus. Nuclear YTHDF1 enhances the binding capacity of SRSF2 to a group of m6A-modified exons, leading to increased exon inclusion. Specifically, YTHDF1 promotes splicing and expression of DNA repair genes, such as BRCA1 and TP53BP1, thereby mitigating excessive DNA damage. Depletion of YTHDF1 sensitizes cancer cells to radiation treatment. Altogether, our study reveals a crucial role of YTHDF1 in m6A-mediated mRNA splicing in the DNA damage response, proposing it as a potential target for radiation therapy. Overall design: [dataset 1] 3 samples. m6A-IP-seq of polyA+ RNA samples, including m6A input, m6A-IP in HEK293T cell line and RNA-seq in YTHDF1-KO HEK293T cells after X-ray exposure [dataset 2] 2 samples. RNA-Seq samples of SRSF2-CTL and SRSF2-KD HEK293T cells after X-ray exposure; [dataset 3] 1 samples. Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP-seq) for YTHDF1 in HEK293T cell line after X-ray exposure;[dataset 4] 2 samples.RNA Immunoprecipitation (RIP-seq) for SRSF2 in YTHDF1-WT/KO HEK293T cell line after X-ray exposure;