Asf1 mediates histone eviction and deposition during elongation by RNA polymerase II

Mol Cell. 2006 May 5;22(3):415-22. doi: 10.1016/j.molcel.2006.03.014.


Histones are rapidly evicted and deposited during transcription by RNA polymerase (Pol) II, but a factor that mediates histone eviction in vivo has not yet been identified. Here, we show that the histone chaperone Asf1 associates with promoters and coding regions of transcriptionally active genes. Asf1 mediates histone H3, but not H2B, eviction and deposition during Pol II elongation, suggesting that nucleosome assembly and disassembly occur in a stepwise fashion. Lastly, Asf1 inhibits internal initiation from cryptic promoters within coding regions. These results strongly suggest that Asf1 functions as an elongation factor to disassemble and reassemble histones during Pol II elongation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Cycle Proteins / metabolism*
  • Chromosomes, Fungal / genetics
  • Genes, Fungal
  • Histones / metabolism*
  • Molecular Chaperones
  • Open Reading Frames / genetics
  • Promoter Regions, Genetic / genetics
  • Protein Binding
  • Protein Transport
  • RNA Polymerase II / metabolism*
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Transcription, Genetic*


  • ASF1 protein, S cerevisiae
  • Cell Cycle Proteins
  • Histones
  • Molecular Chaperones
  • Saccharomyces cerevisiae Proteins
  • RNA Polymerase II