RBM45 is an m6A-binding protein that affects neuronal differentiation and the splicing of a subset of pre-mRNAs I

Here, we identify RNA-binding motif containing protein 45 (RBM45) as a novel m6A reader, enriched in the brain, and highly expressed during embryonic neurodevelopment. We demonstrate that RBM45 recognizes intronic m6A and that its primary role is as a direct regulator of pre-mRNA splicing for its target genes, many of which are associated with neurodevelopment. Furthermore, we show that RBM45 is absolutely required for proper differentiation in cultured SH-SY5Y neuroblastoma cells, and that RBM45 regulates splicing of neurodevelopmental target genes central to the activation of gene expression programs that regulate differentiation in vitro. Overall design: Transcriptomic profiling of RBM45 binding sites and target genes (CLIP-seq) in wild-type (WT) and m6A-depleted (METTL3 KO) HEK293T cells expressing FLAG-HA-RBM45