Genetics. Published Articles Ahead of Print: April 2, 2006, Copyright © 2006
doi:10.1534/genetics.105.050195


A more recent version of this article appeared on June 1, 2006.

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Histone H1 of Saccharomyces cerevisiae inhibits transcriptional silencing

Marie Veron 1, Yanfei Zou 2, Qun Yu 2, Xin Bi 2, Abdelkader Selmi 1, Eric Gilson 3 and Pierre-Antoine Defossez 1*

1 Inst. Curie, CNRS
2 University of Rochester
3 ENS Lyon, CNRS

* To whom correspondence should be addressed. E-mail: defossez{at}curie.fr.

Submitted on August 30, 2005
Revised on October 31, 2005
Accepted on 21 March 2006


Abstract

Eukaryotic genomes contain euchromatic regions, that are transcriptionally active, and heterochromatic regions, that are repressed. These domains are separated by "barrier elements": DNA sequences that protect euchromatic regions from encroachment by neighboring heterochromatin. To identify proteins that play a role in the function of barrier elements, we have carried out a screen in S. cerevisiae. We recovered the gene HHO1, which encodes the yeast orthologue of histone H1, as a high-copy modifier of barrier activity. Histone H1 is a linker histone that binds the outside of nucleosomes and modifies chromatin dynamics. Here we show that HHO1p reinforces the action of several types of barrier elements, and also inhibits silencing on its own.

Key Words: Heterochromatin, Histones, Saccharomyces cerevisiae, Silencing, Transcription