Human SMN C2A-2B-3-4 OE (LC-MS/MS)

Spinal muscular atrophy (SMA) genes SMN1/SMN2 produce multiplecircular RNAs (circRNAs), including C2A-2B-3-4that encompassesearly exons 2A, 2B, 3 and 4. Here we report the transcriptome-and proteome-wide effects of overexpression of C2A-2B-3-4 in inducible HEK293 cells. Our RNA-Seq analysisrevealedaltered expression of ~15% genes (4,172 genes) by C2A-2B-3-4. About half of the affected genes by C2A-2B-3-4 remained unaffected by L2A-2B-3-4, a linear transcript encompassing exons 2A, 2B, 3 and 4 of SMN1/SMN2.These findings underscore theuniquerole of the structural context of C2A-2B-3-4 in gene regulation. A surprisingly high numberof upregulated genes by C2A-2B-3-4 were located on chromosomes 4 and 7, whereas many of the downregulated genes were located on chromosomes 10 and X. Supporting a cross-regulation of SMN1/SMN2transcripts, C2A-2B-3-4 and L2A-2B-3-4upregulated and downregulatedSMN1/SMN2mRNAs, respectively. Proteome analysis revealed 61 upregulated and 57 downregulated proteins by C2A-2B-3-4 with very limited overlap with those affected by L2A-2B-3-4. Independent validations confirmed the effect ofC2A-2B-3-4on expression ofgenesassociated with chromatin remodeling, transcription, spliceosome function, ribosome biogenesis, lipid metabolism, cytoskeletal formation, cell proliferationand neuromuscular junction formation. Our findings reveal a broad role of C2A-2B-3-4, a universally expressed circRNA produced by SMN1/SMN2.