Alternative splicing analysis of SRRM1 or SRRM2 targets in THP-1 cells

We reported the joint SRRM1/2 regulation is not the major mechanism of SRRM2-mediated alternative splicing, and that maintenance of splicing condensates by SRRM2 is important for proper alternative splicing. We knocked SRRM1/2 down with three different shRNAs, performed RNA-seq and derived the differential alternative splicing events (DASEs) using rMATS. DASEs of SRRM1/2 were largely different with little overlap, and displayed a different splicing pattern. SRRM2 deficiency induces skipping of cassette exons with short introns and weak 5' splice. Nearly 25% of the skipped events upon SRRM2 knockdown were unannotated. More than 40% of validated DASEs upon SRRM2 suppression were associated with protein domain change (>50% domain removed by splicing). Domain changes, and especially large region removal by multiple exon skipping is a significant mechanism for protein dysfunction. Thus, alternative splicing is the major mechanism for the maintenance of protein function and cell homeostasis by SRRM2. Overall design: Transcriptome profiles and alternative splicing analysis of THP-1 cell lines with either SRRM1 or SRRM2 knockdown, by three different shRNAs respectively