title: A conserved RING finger protein required for histone H2B monoubiquitination and cell size control.
abstract: Monoubiquitination of histone H2B is required for methylation of histone H3 on lysine 4 (K4), a modification associated with active chromatin. The identity of the cognate ubiquitin ligase is unknown. We identify Bre1 as an evolutionarily conserved RING finger protein required in vivo for both H2B ubiquitination and H3 K4 methylation. The RING domain of Bre1 is essential for both of these modifications as is Lge1 (Large 1), a protein required for cell size control that copurifies with Bre1. In cells lacking the euchromatin-associated histone variant H2A.Z, BRE1, RAD6, and LGE1 are each essential for cell viability, supporting redundant functions for H2B ubiquitination and H2A substitution in the formation of active chromatin. Notably, analysis of mutants demonstrates a function for Bre1/Lge1-dependent H2B monoubiquitination in the control of cell size.
authors.affiliation: Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA.
authors.forename: William W
authors.initials: WW
authors.lastname: Hwang
authors.forename: Shivkumar
authors.initials: S
authors.lastname: Venkatasubrahmanyam
authors.forename: Alexandra G
authors.initials: AG
authors.lastname: Ianculescu
authors.forename: Amy
authors.initials: A
authors.lastname: Tong
authors.forename: Charles
authors.initials: C
authors.lastname: Boone
authors.forename: Hiten D
authors.initials: HD
authors.lastname: Madhani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D048429:Cell Size; D006657:Histones / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008745:Methylation; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D025801:Ubiquitin / Q000378:metabolism*
chemical_list: C472168:Bre1 protein, S cerevisiae; D006657:Histones; D046911:Macromolecular Substances; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin