title: Uracil DNA N-glycosylase promotes assembly of human centromere protein A.
abstract: Uracil is removed from DNA by the conserved enzyme uracil DNA N-glycosylase (UNG). Previously, we observed that inhibiting UNG in Xenopus egg extracts blocked assembly of CENP-A, a histone H3 variant. CENP-A is an essential protein in all species, since it is required for chromosome segregation during mitosis. Thus, the implication of UNG in CENP-A assembly implies that UNG would also be essential, but UNG mutants lacking catalytic activity are viable in all species. In this paper, we present evidence that UNG2 colocalizes with CENP-A and H2AX phosphorylation at centromeres in normally cycling cells. Reduction of UNG2 in human cells blocks CENP-A assembly, and results in reduced cell proliferation, associated with increased frequencies of mitotic abnormalities and rapid cell death. Overexpression of UNG2 induces high levels of CENP-A assembly in human cells. Using a multiphoton laser approach, we demonstrate that UNG2 is rapidly recruited to sites of DNA damage. Taken together, our data are consistent with a model in which the N-terminus of UNG2 interacts with the active site of the enzyme and with chromatin.
authors.affiliation: Moores UCSD Cancer Center and Ludwig Institute for Cancer Research, University of California San Diego, La Jolla, California, United States of America. szeitlin@sciencegeeks.org
authors.forename: Samantha G
authors.initials: SG
authors.lastname: Zeitlin
authors.forename: Brian R
authors.initials: BR
authors.lastname: Chapados
authors.forename: Norman M
authors.initials: NM
authors.lastname: Baker
authors.forename: Caroline
authors.initials: C
authors.lastname: Tai
authors.forename: Geir
authors.initials: G
authors.lastname: Slupphaug
authors.forename: Jean Y J
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis; D001324:Autoantigens / Q000378:metabolism*; D002503:Centromere / Q000378:metabolism; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004249:DNA Damage; D045647:DNA Glycosylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016195:G2 Phase; D049452:Green Fluorescent Proteins / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D007834:Lasers; D010766:Phosphorylation; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014158:Transcription, Genetic; D014981:Xenopus; D054325:vpr Gene Products, Human Immunodeficiency Virus / Q000378:metabolism
chemical_list: D001324:Autoantigens; C000619700:CENPA protein, human; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; C468783:H2AX protein, human; D006657:Histones; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D054325:vpr Gene Products, Human Immunodeficiency Virus; D049452:Green Fluorescent Proteins; C492570:CCNO protein, human; D045647:DNA Glycosylases