Molecular Cell
Volume 35, Issue 3, 14 August 2009, Pages 377-383
Journal home page for Molecular Cell

Short Article
Histone Chaperone Spt16 Promotes Redeposition of the Original H3-H4 Histones Evicted by Elongating RNA Polymerase

https://doi.org/10.1016/j.molcel.2009.07.001Get rights and content
Under an Elsevier user license
open archive

Summary

Nucleosomes are surprisingly dynamic structures in vivo, showing transcription-independent exchange of histones H2A-H2B genome-wide and exchange of H3-H4 mainly within the promoters of transcribed genes. In addition, nucleosomes are disrupted in front of and reassembled behind the elongating RNA polymerase. Here we show that inactivation of histone chaperone Spt16 in yeast results in rapid loss of H2B and H3 from transcribed genes but also from inactive genes. In all cases, histone loss is blocked by a transcription inhibitor, indicating a transcription-dependent event. Thus, nucleosomes are efficiently evicted by the polymerase but do not reform in the absence of Spt16. Yet exchange of nucleosomal H2B with free histones occurs normally, and, unexpectedly, incorporation of new H3 increases at all loci tested. This points to Spt16 restoring normal nucleosome structure by redepositing the displaced H3-H4 histones, thereby preventing incorporation of new histones and perhaps changes in histone modification patterns associated with ongoing transcription.

DNA

Cited by (0)