macroH2A1 drives nucleosome dephasing and genome instability in histone humanized yeast
Max A.B. Haase,
Luciana Lazar-Stefanita,
Guðjón Ólafsson,
Aleksandra Wudzinska,
Michael J. Shen,
David M. Truong,
Jef D. Boeke
Affiliations
Max A.B. Haase
Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA; Vilcek Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY 10016, USA
Luciana Lazar-Stefanita
Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
Guðjón Ólafsson
Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
Aleksandra Wudzinska
Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
Michael J. Shen
Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
David M. Truong
Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA; Department of Pathology, NYU Langone Health, New York, NY 10016, USA
Jef D. Boeke
Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA; Corresponding author
Summary: In addition to replicative histones, eukaryotic genomes encode a repertoire of non-replicative variant histones, providing additional layers of structural and epigenetic regulation. Here, we systematically replace individual replicative human histones with non-replicative human variant histones using a histone replacement system in yeast. We show that variants H2A.J, TsH2B, and H3.5 complement their respective replicative counterparts. However, macroH2A1 fails to complement, and its overexpression is toxic in yeast, negatively interacting with yeast’s native histones and kinetochore genes. To isolate yeast with macroH2A1 chromatin, we uncouple the effects of its macro and histone fold domains, revealing that both domains suffice to override native nucleosome positioning. Furthermore, both uncoupled constructs of macroH2A1 exhibit lower nucleosome occupancy, decreased short-range chromatin interactions (<20 kb), disrupted centromeric clustering, and increased chromosome instability. Our observations demonstrate that lack of a canonical histone H2A dramatically alters chromatin organization in yeast, leading to genome instability and substantial fitness defects.
