DNA-mediated association of two histone-bound complexes of yeast Chromatin Assembly Factor-1 (CAF-1) drives tetrasome assembly in the wake of DNA replication
Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, United States; Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
Tejas Yadav
Weill Cornell Graduate School of Medical Sciences, New York, United States; Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
Jeremy L Balsbaugh
Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, United States
Michael R Harris
Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, United States
Eileen S Findlay
Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, United States
Yang Liu
Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, United States
Catherine A Radebaugh
Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
Laurie A Stargell
Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States; Institute for Genome Architecture and Function, Colorado State University, Fort Collins, United States
Natalie G Ahn
Biofrontiers Institute, University of Colorado Boulder, Boulder, United States
Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, United States; Institute for Genome Architecture and Function, Colorado State University, Fort Collins, United States
Nucleosome assembly in the wake of DNA replication is a key process that regulates cell identity and survival. Chromatin assembly factor 1 (CAF-1) is a H3-H4 histone chaperone that associates with the replisome and orchestrates chromatin assembly following DNA synthesis. Little is known about the mechanism and structure of this key complex. Here we investigate the CAF-1•H3-H4 binding mode and the mechanism of nucleosome assembly. We show that yeast CAF-1 binding to a H3-H4 dimer activates the Cac1 winged helix domain interaction with DNA. This drives the formation of a transient CAF-1•histone•DNA intermediate containing two CAF-1 complexes, each associated with one H3-H4 dimer. Here, the (H3-H4)2 tetramer is formed and deposited onto DNA. Our work elucidates the molecular mechanism for histone deposition by CAF-1, a reaction that has remained elusive for other histone chaperones, and it advances our understanding of how nucleosomes and their epigenetic information are maintained through DNA replication.
