eLife (Sep 2016)

The Cac1 subunit of histone chaperone CAF-1 organizes CAF-1-H3/H4 architecture and tetramerizes histones

  • Wallace H Liu,
  • Sarah C Roemer,
  • Yeyun Zhou,
  • Zih-Jie Shen,
  • Briana K Dennehey,
  • Jeremy L Balsbaugh,
  • Jennifer C Liddle,
  • Travis Nemkov,
  • Natalie G Ahn,
  • Kirk C Hansen,
  • Jessica K Tyler,
  • Mair EA Churchill

DOI
https://doi.org/10.7554/eLife.18023
Journal volume & issue
Vol. 5

Abstract

Read online

The histone chaperone Chromatin Assembly Factor 1 (CAF-1) deposits tetrameric (H3/H4)2 histones onto newly-synthesized DNA during DNA replication. To understand the mechanism of the tri-subunit CAF-1 complex in this process, we investigated the protein-protein interactions within the CAF-1-H3/H4 architecture using biophysical and biochemical approaches. Hydrogen/deuterium exchange and chemical cross-linking coupled to mass spectrometry reveal interactions that are essential for CAF-1 function in budding yeast, and importantly indicate that the Cac1 subunit functions as a scaffold within the CAF-1-H3/H4 complex. Cac1 alone not only binds H3/H4 with high affinity, but also promotes histone tetramerization independent of the other subunits. Moreover, we identify a minimal region in the C-terminus of Cac1, including the structured winged helix domain and glutamate/aspartate-rich domain, which is sufficient to induce (H3/H4)2 tetramerization. These findings reveal a key role of Cac1 in histone tetramerization, providing a new model for CAF-1-H3/H4 architecture and function during eukaryotic replication.

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