Spt16 and Pob3 of Saccharomyces cerevisiae form an essential, abundant heterodimer that is nuclear, chromatin-associated, and copurifies with DNA polymerase alpha

Biochemistry. 1999 Jul 13;38(28):8961-71. doi: 10.1021/bi982851d.

Abstract

Previously we showed that the yeast proteins Spt16 (Cdc68) and Pob3 are physically associated, and interact physically and genetically with the catalytic subunit of DNA polymerase alpha, Pol1 [Wittmeyer and Formosa (1997) Mol. Cell. Biol. 17, 4178-4190]. Here we show that purified Spt16 and Pob3 form a stable, abundant, elongated heterodimer and provide evidence that this is the functional form of these proteins. Genetic interactions between mutations in SPT16 and POB3 support the importance of the Spt16-Pob3 interaction in vivo. Spt16, Pob3, and Pol1 proteins were all found to localize to the nucleus in S. cerevisiae. A portion of the total cellular Spt16-Pob3 was found to be chromatin-associated, consistent with the proposed roles in modulating chromatin function. Some of the Spt16-Pob3 complex was found to copurify with the yeast DNA polymerase alpha/primase complex, further supporting a connection between Spt16-Pob3 and DNA replication.

MeSH terms

  • Acetyltransferases / metabolism
  • Adenosine Triphosphatases / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / isolation & purification
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / isolation & purification
  • Cell Cycle Proteins / metabolism*
  • Chromatin / metabolism*
  • Chromatography, Affinity
  • Chromatography, Gel
  • Chromatography, Ion Exchange
  • DNA Polymerase I / isolation & purification*
  • DNA Polymerase I / metabolism
  • Dimerization
  • Durapatite
  • Enzyme Activation
  • Fungal Proteins / genetics
  • Fungal Proteins / isolation & purification
  • Fungal Proteins / metabolism*
  • Histone Acetyltransferases
  • Immunoblotting
  • Macromolecular Substances
  • Nuclear Proteins / genetics
  • Nuclear Proteins / isolation & purification
  • Nuclear Proteins / metabolism*
  • Peptide Chain Elongation, Translational
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*
  • Transcription Factors*
  • Transcriptional Elongation Factors

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • Chromatin
  • Fungal Proteins
  • Macromolecular Substances
  • Nuclear Proteins
  • POB3 protein, S cerevisiae
  • SPT16 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Transcriptional Elongation Factors
  • Durapatite
  • Acetyltransferases
  • Histone Acetyltransferases
  • DNA Polymerase I
  • Adenosine Triphosphatases