title: Msl2 is a novel component of the vertebrate DNA damage response.
abstract: hMSL2 (male-specific lethal 2, human) is a RING finger protein with ubiquitin ligase activity. Although it has been shown to target histone H2B at lysine 34 and p53 at lysine 351, suggesting roles in transcription regulation and apoptosis, its function in these and other processes remains poorly defined. To further characterize this protein, we have disrupted the Msl2 gene in chicken DT40 cells. Msl2(-/-) cells are viable, with minor growth defects. Biochemical analysis of the chromatin in these cells revealed aberrations in the levels of several histone modifications involved in DNA damage response pathways. DNA repair assays show that both Msl2(-/-) chicken cells and hMSL2-depleted human cells have defects in non-homologous end joining (NHEJ) repair. DNA damage assays also demonstrate that both Msl2 and hMSL2 proteins are modified and stabilized shortly after induction of DNA damage. Moreover, hMSL2 mediates modification, presumably ubiquitylation, of a key DNA repair mediator 53BP1 at lysine 1690. Similarly, hMSL1 and hMOF (males absent on the first) are modified in the presence of hMSL2 shortly after DNA damage. These data identify a novel role for Msl2/hMSL2 in the cellular response to DNA damage. The kinetics of its stabilization suggests a function early in the NHEJ repair pathway. Moreover, Msl2 plays a role in maintaining normal histone modification profiles, which may also contribute to the DNA damage response.
authors.affiliation: Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, University Road, Galway, Ireland.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Lai
authors.forename: Simona
authors.initials: S
authors.lastname: Moravcová
authors.forename: Yvan
authors.initials: Y
authors.lastname: Canitrot
authors.forename: Lukasz P
authors.initials: LP
authors.lastname: Andrzejewski
authors.forename: Dervla M
authors.initials: DM
authors.lastname: Walshe
authors.forename: Stephen
authors.initials: S
authors.lastname: Rea
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002645:Chickens; D004249:DNA Damage; D059766:DNA End-Joining Repair; D004260:DNA Repair; D055786:Gene Knockout Techniques; D018390:Gene Targeting; D051548:Histone Acetyltransferases / Q000378:metabolism; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism; D018345:Mice, Knockout; D055550:Protein Stability; D000071857:Tumor Suppressor p53-Binding Protein 1; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; C498301:TP53BP1 protein, human; D000071857:Tumor Suppressor p53-Binding Protein 1; D051548:Histone Acetyltransferases; C496552:KAT8 protein, human; C544740:MSL1 protein, human; C560942:MSL2 protein, human; D044767:Ubiquitin-Protein Ligases