The Cyc8 (Ssn6)-Tup1 corepressor complex is composed of one Cyc8 and four Tup1 subunits - PubMed (original) (raw)

The Cyc8 (Ssn6)-Tup1 corepressor complex is composed of one Cyc8 and four Tup1 subunits

U S Varanasi et al. Mol Cell Biol. 1996 Dec.

Abstract

The Cyc8 (Ssn6)-Tup1 corepressor complex is required for repression in several important regulatory systems in yeast cells, including glucose repression and mating type. Cyc8-Tup1 is recruited to target genes by interaction with diverse repressor proteins that bind directly to DNA. Since the complex has a large apparent molecular mass of 1,200 kDa on nondenaturing gels (F. E. Williams, U. Varanasi, and R. J. Trumbly, Mol. Cell. Biol. 11:3307-3316, 1991), we used a variety of approaches to determine its actual subunit composition. Immunoprecipitation of epitope-tagged complex and reconstitution of the complex from in vitro-translated proteins demonstrated that only the Cyc8 and Tup1 proteins were present in the complex. Hydrodynamic properties showed that these proteins have unusually large Stokes radii, low sedimentation coefficients, and high frictional ratios, all characteristic of asymmetry which partly accounts for the apparent high molecular weight. Calculation of native molecular weights from these properties indicated that the Cyc8-Tup1 complex is composed of one Cyc8 subunit and four Tup1 subunits. This composition was confirmed by reconstitution of the complex from Cyc8 and Tup1 expressed in vitro and analysis by one- and two-dimensional gel electrophoresis.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Electrophoresis. 1991 Oct;12(10):703-9 - PubMed
    1. Cell. 1992 Feb 21;68(4):709-19 - PubMed
    1. Mol Cell Biol. 1993 Jun;13(6):3481-6 - PubMed
    1. Nucleic Acids Res. 1993 Jul 11;21(14):3295-300 - PubMed
    1. Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1950-4 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources