A novel set of spliceosome-associated proteins and the essential splicing factor PSF bind stably to pre-mRNA prior to catalytic step II of the splicing reaction - PubMed (original) (raw)

A novel set of spliceosome-associated proteins and the essential splicing factor PSF bind stably to pre-mRNA prior to catalytic step II of the splicing reaction

O Gozani et al. EMBO J. 1994.

Abstract

We have isolated and determined the protein composition of the spliceosomal complex C. The pre-mRNA in this complex has undergone catalytic step I, but not step II, of the splicing reaction. We show that a novel set of 14 spliceosome-associated proteins (SAPs) and the essential splicing factor PSF are specifically associated with the C complex, implicating these proteins in catalytic step II. Significantly, immunodepletion and biochemical complementation studies demonstrate directly that PSF is essential for catalytic step II. Purified PSF is known to UV crosslink to pyrimidine tracts, and our data show that PSF UV crosslinks to pre-mRNA in purified C complex. Thus, PSF may replace the 3' splice site binding factor U2AF65 which is destabilized during spliceosome assembly. Finally, we show that SAPs 60 and 90, which are present in both the B and C complexes, are specifically associated with U4 and U6 snRNPs, and thus may have important roles in the functioning of these snRNPs during the splicing reaction.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Genes Dev. 1990 Jul;4(7):1185-96 - PubMed
    1. Proc Natl Acad Sci U S A. 1990 Oct;87(20):8031-5 - PubMed
    1. Cell. 1986 Sep 12;46(6):845-55 - PubMed
    1. Cell. 1986 Dec 5;47(5):755-66 - PubMed
    1. Cell. 1986 Dec 26;47(6):973-84 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources