Histone H3 Lysine 36 Methylation Targets the Isw1b Remodeling Complex to Chromatin

Abstract

Histone H3 lysine 36 methylation is a ubiquitous hallmark of productive transcription elongation. Despite the prevalence of this histone posttranslational modification, however, the downstream functions triggered by this mark are not well understood. In this study, we showed that H3K36 methylation promoted the chromatin interaction of the Isw1b chromatin-remodeling complex in Saccharomyces cerevisiae. Similar to H3K36 methylation, Isw1b was found at the mid- and 3′ regions of transcribed genes genome wide, and its presence at active genes was dependent on H3K36 methylation and the PWWP domain of the Isw1b subunit, Ioc4. Moreover, purified Isw1b preferentially interacted with recombinant nucleosomes that were methylated at lysine 36, and this interaction also required the Ioc4 PWWP domain. While H3K36 methylation has been shown to regulate the binding of numerous factors, this is the first time that it has been shown to facilitate targeting of a chromatin-remodeling complex.

ACKNOWLEDGMENTS

Support for this work was provided by grants to L.J.H. from the Natural Sciences and Engineering Research Council of Canada (RGPIN 262102-08) and to M.S.K. from the Canadian Institutes of Health Research (MOP-79442). V.E.M. and J.M.S. were supported by fellowships from the University of British Columbia and the Child and Family Research Institute, respectively. B.J.E. and I.J. were supported by Natural Sciences and Engineering Research Council of Canada MGS awards. T.H. was a fellow of the CIHR/MSFHR Bioinformatics Training Program. M.S.K. is a Scholar of the Michael Smith Foundation for Health Research and the Canadian Institute for Advanced Research.

We thank Fred Winston for the provision of strains and plasmids.