Hereditary Genetics: Current Research

H2A.Z: stable or not stable that is the question

4^th International Congress on Epigenetics & Chromatin

September 03-05, 2018 | London, UK

Laszlo Imre, Gabor Szabo, Juan Ausio, Gergo Kallo, Eva Csosz, Hiroshi Kimura and Masahiko Harata

University of Debrecen, Hungary
University of Victoria, Canada
Institute of Innovative Research - Tokyo Institute of Technology, Japan
Tohoku University, Japan

Posters & Accepted Abstracts: Hereditary Genet Curr Res

Abstract:

Nucleosomal structure is repressive therefore; the mechanisms involved in the regulation of nucleosome stability are of great importance in the control of gene expression. It is well established that nucleosome free regions (NFRs) are generated at the transcriptional start sites, flanked by nucleosomes with high turnover rate and of special histone composition. H2A.Z is one of these histone variants, characteristic for the +1 and -1 nucleosomes neighbouring these NFRs, among its other preferential locations. We have developed an in situ assay for the measurement of the intrinsic and super helicity dependent nucleosome stability. Using this assay NFR flanking nucleosomes carrying H3K4me3 histone post-translational modification were found to be less stable compared to nucleosomes carrying heterochromatic histone marks. Since H2A.Z can substitute canonical H2A histones in the NFR flanking nucleosomes, we expected that the H2A.Z containing nucleosomes would also be destabilized. Using H2A.Z specific antibodies and fluorophores tagged H2A.Z histones, we observed unusually stable. H2A.Z containing nucleosomes that could be detected in an antibody clone/brand dependent manner. Having compared different antibodies and H2A.Z isotypes we have shown that neither the acetylation of the N-terminal histone tail nor the isotype was responsible for their increased stability. Through the spectacles of super-helicity dependent stability, the unusually stable nucleosomes appear to constitute a sub population of all H2A.Z containing nucleosomes that appears to be of perinucleolar localization. Recent Publications: 1. Imre et al. (2017) Nucleosome stability measured in situ by automated quantitative imaging. Scientific Reports 7(1):12734.

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