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. Transcriptome profiles and alternative splicing analysis of THP-1 cell lines with either SRRM1 or SRRM2 knockdown, by three different shRNAs respectively