title: NBS1 localizes to gamma-H2AX foci through interaction with the FHA/BRCT domain.
abstract: DNA double-strand breaks represent the most potentially serious damage to a genome; hence, many repair proteins are recruited to nuclear damage sites by as yet poorly characterized sensor mechanisms. Here, we show that NBS1, the gene product defective in Nijmegen breakage syndrome (NBS), physically interacts with histone, rather than damaged DNA, by direct binding to gamma-H2AX. We also demonstrate that NBS1 binding can occur in the absence of interaction with hMRE11 or BRCA1. Furthermore, this NBS1 physical interaction was reduced when anti-gamma-H2AX antibody was introduced into normal cells and was also delayed in AT cells, which lack the kinase activity for phosphorylation of H2AX. NBS1 has no DNA binding region but carries a combination of the fork-head associated (FHA) and the BRCA1 C-terminal domains (BRCT). We show that the FHA/BRCT domain of NBS1 is essential for this physical interaction, since NBS1 lacking this domain failed to bind to gamma-H2AX in cells, and a recombinant FHA/BRCT domain alone can bind to recombinant gamma-H2AX. Consequently, the FHA/BRCT domain is likely to have a crucial role for both binding to histone and for relocalization of hMRE11/hRAD50 nuclease complex to the vicinity of DNA damage.
authors.affiliation: Department of Oral and Maxillo Facial Radiology, Hiroshima University, Hiroshima 734-8553, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tauchi
authors.forename: Shuichi
authors.initials: S
authors.lastname: Sakamoto
authors.forename: Asako
authors.initials: A
authors.lastname: Nakamura
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Morishima
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsuura
authors.forename: Toshiko
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Tamai
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanimoto
authors.forename: Kenshi
authors.initials: K
authors.lastname: Komatsu
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D051858:Forkhead Transcription Factors; D006657:Histones / Q000378:metabolism*; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D051858:Forkhead Transcription Factors; D006657:Histones; C112156:NBN protein, human; D009687:Nuclear Proteins; D014157:Transcription Factors