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XB-ART-46611
Nucleic Acids Res. November 1, 2012; 40 (20): 10139-49.

Yeast CAF-1 assembles histone (H3-H4)2 tetramers prior to DNA deposition.

Winkler DD , Zhou H , Dar MA , Zhang Z , Luger K .


Abstract
Following acetylation, newly synthesized H3-H4 is directly transferred from the histone chaperone anti-silencing factor 1 (Asf1) to chromatin assembly factor 1 (CAF-1), another histone chaperone that is critical for the deposition of H3-H4 onto replicating DNA. However, it is unknown how CAF-1 binds and delivers H3-H4 to the DNA. Here, we show that CAF-1 binds recombinant H3-H4 with 10- to 20-fold higher affinity than H2A-H2B in vitro, and H3K56Ac increases the binding affinity of CAF-1 toward H3-H4 2-fold. These results provide a quantitative thermodynamic explanation for the specific H3-H4 histone chaperone activity of CAF-1. Surprisingly, H3-H4 exists as a dimer rather than as a canonical tetramer at mid-to-low nanomolar concentrations. A single CAF-1 molecule binds a cross-linked (H3-H4)2 tetramer, or two H3-H4 dimers that contain mutations at the (H3-H4)2 tetramerization interface. These results suggest that CAF-1 binds to two H3-H4 dimers in a manner that promotes formation of a (H3-H4)2 tetramer. Consistent with this idea, we confirm that CAF-1 synchronously binds two H3-H4 dimers derived from two different histone genes in vivo. Together, the data illustrate a clear mechanism for CAF-1-associated H3-H4 chaperone activity in the context of de novo nucleosome (re)assembly following DNA replication.

PubMed ID: 22941638
PMC ID: PMC3488248
Article link: Nucleic Acids Res.
Grant support: F32GM096531 NIGMS NIH HHS , GM- 067777 NIGMS NIH HHS , GM72719 NIGMS NIH HHSHoward Hughes Medical Institute , R01 GM072719 NIGMS NIH HHS , P50 CA108961 NCI NIH HHS , F32GM096531 NIGMS NIH HHS , R01 GM072719 NIGMS NIH HHS , GM72719 NIGMS NIH HHSHoward Hughes Medical Institute , GM- 067777 NIGMS NIH HHS

Genes referenced: acvrl1 asf1a cnot7 hist2h2ab hist2h2be ncr3


References:
Andrews, 2008, Pubmed, Xenbase[+]


Article Images: [+] show captions

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