The structure of the yFACT Pob3-M domain, its interaction with the DNA replication factor RPA, and a potential role in nucleosome deposition

Mol Cell. 2006 May 5;22(3):363-74. doi: 10.1016/j.molcel.2006.03.025.


We report the crystal structure of the middle domain of the Pob3 subunit (Pob3-M) of S. cerevisiae FACT (yFACT, facilitates chromatin transcription), which unexpectedly adopts an unusual double pleckstrin homology (PH) architecture. A mutation within a conserved surface cluster in this domain causes a defect in DNA replication that is suppressed by mutation of replication protein A (RPA). The nucleosome reorganizer yFACT therefore interacts in a physiologically important way with the central single-strand DNA (ssDNA) binding factor RPA to promote a step in DNA replication. Purified yFACT and RPA display a weak direct physical interaction, although the genetic suppression is not explained by simple changes in affinity between the purified proteins. Further genetic analysis suggests that coordinated function by yFACT and RPA is important during nucleosome deposition. These results support the model that the FACT family has an essential role in constructing nucleosomes during DNA replication, and suggest that RPA contributes to this process.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / chemistry
  • DNA Replication / genetics
  • Gene Expression
  • Histones / metabolism
  • Models, Genetic
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation / genetics
  • Nucleosomes / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein Subunits
  • Replication Protein A / metabolism*
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Suppression, Genetic / genetics
  • Transcription Factors / chemistry*
  • Transcription Factors / metabolism*
  • Transcriptional Elongation Factors


  • Carrier Proteins
  • Cell Cycle Proteins
  • Histones
  • Nucleosomes
  • POB3 protein, S cerevisiae
  • Protein Subunits
  • Replication Protein A
  • SPT16 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Transcriptional Elongation Factors

Associated data

  • PDB/2GCJ
  • PDB/2GCL