Dephosphorylation of NSSR1 regulates alternative splicing of the GluR-B minigene

Abstract

ABSTRACT. Neural salient serine/arginine-rich protein 1 (NSSR1, alternatively SRp38) is an important splicing factor that can repress pre-mRNA alternative splicing in cells during heat shock and mitosis. We show here that NSSR1 protein is dephosphorylated when cells are heat shocked or incubated with kinase inhibitor K252a. Both heat shock and K252a treatment increase the truncated splicing isoform of the GluR-B minigene pre-mRNA. We also investigated the roles of the RRM motif and three RS domains of NSSR1 in in vivo pre-mRNA splicing. The results show that deletion of the RRM motif did not affect GluR-B minigene pre-mRNA splicing, but deletion of any one of the three RS domains increases the truncated splicing isoform of the GluR-B minigene. We further show that an SRSRSK sequence in the RS3 domain may play an important role in the function of NSSR1 in pre-mRNA splicing.

Identification of two short peptide motifs from serine/arginine-rich protein ribonucleic acid recognition motif-1 domain acting as splicing regulators

“…The domain analysis of the four SR proteins indicates that RRM1/2 conferred splicing functions other than RNA binding, which is consistent with previous studies ( Zhang et al, 2014 ; Lee et al, 2017 ); and in the context of SMN1/2 exon 7 inclusion, they acted as splicing activators when bound to the upstream intron with only one exception of CP-RRM1 of SRSF9 that was neutral, whereas they acted as splicing repressors or had no effects when bound to the downstream intron.…”

“…RS domains are thought to function in recruiting components of the basal splicing machinery through protein-protein interactions ( Phelan et al, 2012 ; Hertel & Graveley, 2005 ). However, splicing can be rescued by SR proteins in an RS domain-independent manner, indicating that RRMs can perform functions other than RNA binding in certain circumstances ( Zhang et al, 2014 ). In cell-free S-100 complementation assays, Zhu & Krainer (2000) showed that the RS domain of SRSF2 is dispensable for constitutively spliced substrates or some substrates with ESEs.…”

SRSF10: an atypical splicing regulator with critical roles in stress response, organ development, and viral replication

“…Transfecting a SRSF10∆RRM derivative did not affect GluR-B splicing, but deleting portions of the RS domains promoted skipping of both exons (Zhang et al 2014).…”

“…5c) (Komatsu et al 1999). Using a minigene model in human PFSK-1 cells subjected to heat-shock, dSRSF10 was associated with a change in the alternative splicing of mutually exclusive flip/flop exons in the Glutamate receptor subunit B (GluR-B) (Zhang et al 2014). Overexpression of SRSF10 promotes flip exon inclusion but depleting SRSF10 in non-heat shock cells has no effect.…”