The snRNP-free U1A (SF-A) complex(es): Identification of the largest subunit as PSF, the polypyrimidine-tract binding protein-associated splicing factor

Carol S. Lutz, Charles Cooke, J. Patrick O'Connor, Ryuji Kobayashi, James C. Alwine

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

We have previously shown that a specific monoclonal antibody prepared against the U1A protein, MAb 12E12, is unique in its ability to recognize a form of U1A which is not associated with the U1snRNP. This unique form of U1A, termed snRNP-free U1A or SF-A, was found to be complexed with a novel set of non-snRNP proteins (O'Connor et al., 1997, RNA 3:1444-1455). Here we demonstrate that the largest protein in these SF-A complex(es), p105, is the polypyrimidine-tract binding protein-associated factor (PSF), an auxiliary splicing factor. We show that PSF copurifies and co-immunoprecipitates with SF-A from 293T cell nucleoplasm and that it interacts with SF-A in vitro. In addition, we show that MAb 12E12 inhibits both splicing and polyadenylation in an in vitro coupled splicing and polyadenylation reaction. This suggests that SF-A and/or the SF-A complex(es) perform an important function in both processing reactions and possibly in last exon definition.

Original languageEnglish (US)
Pages (from-to)1493-1499
Number of pages7
JournalRNA
Volume4
Issue number12
DOIs
StatePublished - Dec 1998

All Science Journal Classification (ASJC) codes

  • Molecular Biology

Keywords

  • Polyadenylation
  • RNA processing
  • SF-A complex
  • SnRNP-free U1A (SF- A)
  • Splicing
  • U1snRNP

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