Activation of Cryptic 3' Splice-Sites by SRSF2 Contributes to Cassette Exon Skipping

Cells. 2019 Jul 10;8(7):696. doi: 10.3390/cells8070696.

Abstract

Here we show that the serine/arginine rich splicing factor 2 (SRSF2) promotes cryptic 3' splice-site (3'AG') usage during cassette exon exclusion in survival of motor neuron (SMN2) minigenes. Deletion of the 3'AG' (3'AG'1), its associated branch point (BP') and polypyrimidine tract (PPT') sequences directs SRSF2 to promote a second 3'AG' (3'AG'2) with less conserved associated region for intron splicing. Furthermore, deletion of both 3'AG'1 and 3'AG'2 and their associated sequences triggered usage of a third 3'AG'3 that has very weak associated sequences. Interestingly, when intron splicing was directed to the 3'AG' cryptic splice-sites, intron splicing from the canonical 3'AG splice-site was reduced along with a decrease in cassette exon inclusion. Moreover, multiple SRSF2 binding sites within the intron are responsible for 3'AG' activation. We conclude that SRSF2 facilitates exon exclusion by activating a cryptic 3'AG' and inhibiting downstream intron splicing.

Keywords: SRSF2; cryptic 3′ splice-site; exon exclusion; intron retention; pre-mRNA splicing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Binding Sites
  • Exons*
  • HEK293 Cells
  • Humans
  • Introns
  • RNA Precursors / genetics
  • RNA Precursors / metabolism
  • RNA Splice Sites
  • RNA Splicing
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / genetics
  • Serine-Arginine Splicing Factors / genetics
  • Serine-Arginine Splicing Factors / metabolism*
  • Survival of Motor Neuron 2 Protein / genetics
  • Survival of Motor Neuron 2 Protein / metabolism

Substances

  • RNA Precursors
  • RNA Splice Sites
  • RNA, Messenger
  • RNA-Binding Proteins
  • SMN2 protein, human
  • Survival of Motor Neuron 2 Protein
  • SRSF2 protein, human
  • Serine-Arginine Splicing Factors