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Updated: Apr 26, 2026
In Vitro Characterization of Histone Chaperones using Analytical, Pull-Down and Chaperoning Assays
Published on: December 29, 2021
The yeast histone chaperone hif1p functions with RNA in nucleosome assembly
Amy R Knapp1, Huanyu Wang1, Mark R Parthun1
1Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio, United States of America.
Background:
Hif1p is an H3/H4-specific histone chaperone that associates with the nuclear form of the Hat1p/Hat2p complex (NuB4 complex) in the yeast Saccharomyces cerevisiae. While not capable of depositing histones onto DNA on its own, Hif1p can act in conjunction with a yeast cytosolic extract to assemble nucleosomes onto a relaxed circular plasmid.
Results:
To identify the factor(s) that function with Hif1p to carry out chromatin assembly, multiple steps of column chromatography were carried out to fractionate the yeast cytosolic extract. Analysis of partially purified fractions indicated that Hif1p-dependent chromatin assembly activity resided in RNA rather than protein. Fractionation of isolated RNA indicated that the chromatin assembly activity did not simply purify with bulk RNA. In addition, the RNA-mediated chromatin assembly activity was blocked by mutations in the human homolog of Hif1p, sNASP, that prevent the association of this histone chaperone with histone H3 and H4 without altering its electrostatic properties.
Conclusions:
These results suggest that specific RNA species may function in concert with histone chaperones to assemble chromatin.
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