title: CAF-1-induced oligomerization of histones H3/H4 and mutually exclusive interactions with Asf1 guide H3/H4 transitions among histone chaperones and DNA.
abstract: Anti-silencing function 1 (Asf1) and Chromatin Assembly Factor 1 (CAF-1) chaperone histones H3/H4 during the assembly of nucleosomes on newly replicated DNA. To understand the mechanism of histone H3/H4 transfer among Asf1, CAF-1 and DNA from a thermodynamic perspective, we developed and employed biophysical approaches using full-length proteins in the budding yeast system. We find that the C-terminal tail of Asf1 enhances the interaction of Asf1 with CAF-1. Surprisingly, although H3/H4 also enhances the interaction of Asf1 with the CAF-1 subunit Cac2, H3/H4 forms a tight complex with CAF-1 exclusive of Asf1, with an affinity weaker than Asf1-H3/H4 or H3/H4-DNA interactions. Unlike Asf1, monomeric CAF-1 binds to multiple H3/H4 dimers, which ultimately promotes the formation of (H3/H4)(2) tetramers on DNA. Thus, transition of H3/H4 from the Asf1-associated dimer to the DNA-associated tetramer is promoted by CAF-1-induced H3/H4 oligomerization.
authors.affiliation: Department of Pharmacology, University of Colorado School of Medicine, Mail Stop 8303, PO Box 6511, Aurora, CO 80045, USA.
authors.forename: Wallace H
authors.initials: WH
authors.lastname: Liu
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Roemer
authors.forename: Alex M
authors.initials: AM
authors.lastname: Port
authors.forename: Mair E A
authors.initials: ME
authors.lastname: Churchill
mesh_terms: D056504:Chromatin Assembly Factor-1 / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D056488:Histone Chaperones / Q000737:chemistry / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding; D055503:Protein Multimerization
chemical_list: D056504:Chromatin Assembly Factor-1; D056488:Histone Chaperones; D006657:Histones; D004247:DNA