title: H2A.Z controls the stability and mobility of nucleosomes to regulate expression of the LH genes.
abstract: The structure and dynamics of promoter chromatin have a profound effect on the expression levels of genes. Yet, the contribution of DNA sequence, histone post-translational modifications, histone variant usage and other factors in shaping the architecture of chromatin, and the mechanisms by which this architecture modulates expression of specific genes are not yet completely understood. Here we use optical tweezers to study the roles that DNA sequence and the histone variant H2A.Z have in shaping the chromatin landscape at the promoters of two model genes, Cga and Lhb. Guided by MNase mapping of the promoters of these genes, we reconstitute nucleosomes that mimic those located near the transcriptional start site and immediately downstream (+1), and measure the forces required to disrupt these nucleosomes, and their mobility along the DNA sequence. Our results indicate that these genes are basally regulated by two distinct strategies, making use of H2A.Z to modulate separate phases of transcription, and highlight how DNA sequence, alternative histone variants and remodelling machinery act synergistically to modulate gene expression.
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Sergei
authors.initials: S
authors.lastname: Rudnizky
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Adaiah
authors.initials: A
authors.lastname: Bavly
authors.affiliation: Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Omri
authors.initials: O
authors.lastname: Malik
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Lilach
authors.initials: L
authors.lastname: Pnueli
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.|Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Philippa
authors.initials: P
authors.lastname: Melamed
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.|Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Ariel
authors.identifier: http://orcid.org/0000-0002-9731-6962
authors.initials: A
authors.lastname: Kaplan