POLE3-POLE4 is a histone H3-H4 chaperone that maintains chromatin integrity during DNA replication Roberto Bellelli Ondrej Belan Valerie E Pye Camille Clement Sarah L Maslen J Mark Skehel Peter Cherepanov Genevieve Almouzni Simon J Boulton 10779/crick.12546671.v1 https://crick.figshare.com/articles/journal_contribution/POLE3-POLE4_is_a_histone_H3-H4_chaperone_that_maintains_chromatin_integrity_during_DNA_replication/12546671 Maintenance of epigenetic integrity relies on coordinated recycling and partitioning of parental histones and deposition of newly synthesized histones during DNA replication. This process depends upon a poorly characterized network of histone chaperones, remodelers, and binding proteins. Here we implicate the POLE3-POLE4 subcomplex of the leading-strand polymerase, PolĪµ, in replication-coupled nucleosome assembly through its ability to selectively bind to histones H3-H4. Using hydrogen/deuterium exchange mass spectrometry and physical mapping, we define minimal domains necessary for interaction between POLE3-POLE4 and histones H3-H4. Biochemical analyses establish that POLE3-POLE4 is a histone chaperone that promotes tetrasome formation and DNA supercoiling in vitro. In cells, POLE3-POLE4 binds both newly synthesized and parental histones, and its depletion hinders helicase unwinding and chromatin PCNA unloading and compromises coordinated parental histone retention and new histone deposition. Collectively, our study reveals that POLE3-POLE4 possesses intrinsic H3-H4 chaperone activity, which facilitates faithful nucleosome dynamics at the replication fork. 2020-06-26 09:41:47 POLE3-POLE4 complex epigenome stability histone chaperone replication-coupled nucleosome assembly Chromatin DNA Polymerase II DNA Polymerase III DNA Replication DNA-Binding Proteins Epigenesis, Genetic Histone Chaperones Histones Humans Molecular Chaperones Nucleoproteins Nucleosomes Poly-ADP-Ribose Binding Proteins Proliferating Cell Nuclear Antigen Protein Binding Boulton FC001048 Cherepanov FC001061 FC-ack PC-ack 06 Biological Sciences 11 Medical and Health Sciences Developmental Biology