Identification and characterization of three members of the human SR family of pre-mRNA splicing factors

G. R. Screaton, J. F. Caceres, A. Mayeda, M. V. Bell, M. Plebanski, D. G. Jackson, J. I. Bell, A. R. Krainer

Research output: Contribution to journalArticleResearchpeer-review

239 Citations (Scopus)

Abstract

SR proteins have a characteristic C-terminal Ser/Arg-rich repeat (RS domain) of variable length and constitute a family of highly conserved nuclear phosphoproteins that can function as both essential and alternative pre-mRNA splicing factors. We have cloned a cDNA encoding a novel human SR protein designated SRp30c, which has an unusually short RS domain. We also cloned cDNAs encoding the human homologues of Drosophila SRp55/B52 and rat SRp40/HRS. Recombinant proteins expressed from these cDNAs are active in constitutive splicing, as shown by their ability to complement a HeLa cell S100 extract deficient in SR proteins. Additional cDNA clones reflect extensive alternative splicing of SRp40 and SRp55 pre-mRNAs. The predicted protein isoforms lack the C-terminal RS domain and might be involved in feedback regulatory loops. The ability of human SRp30c, SRp40 and SRp55 to modulate alternative splicing in vivo was compared with that of other SR proteins using a transient cotransfection assay. The overexpression of individual SR proteins in HeLa cells affected the choice of alternative 5' splice sites of adenovirus E1A and/or human β-thalassemia reporters. The resulting splicing patterns were characteristic for each SR protein. Consistent with the postulated importance of SR proteins in alternative splicing in vivo, we demonstrate complex changes in the levels of mRNAs encoding the above SR proteins upon T cell activation, concomitant with changes in the expression of alternatively spliced isoforms of CD44 and CD45.

Original languageEnglish
Pages (from-to)4336-4349
Number of pages14
JournalThe EMBO Journal
Volume14
Issue number17
Publication statusPublished - 1995
Externally publishedYes

Keywords

  • Alternative splicing
  • RNA splicing
  • SR proteins

Cite this