title: Identification of the autoantigen HB as the barrier-to-autointegration factor.
abstract: The HB autoantigen, a 10-kDa DNA-binding protein recognized by autoantibodies only when bound to DNA, was identified by two-dimensional electrophoresis. Silver-stained protein spots corresponding to the antigen were excised from two-dimensional electrophoresis gels, digested with trypsin, and analyzed by matrix-assisted laser desorption/ionization-reflectron time of flight and nano-electrospray ionization-ion trap/mass spectrometry. Data base search identified the HB antigen as the barrier-to-autointegration factor, a cellular protein implicated in the cellular cycle that blocks autointegration and promotes intermolecular integration of retrovirus such as the Moloney murine leukemia and the human immunodeficiency type 1 virus. The physicochemical characteristics described for these proteins, their ability to bind double-stranded DNA but not single-stranded DNA, and their nuclear localization confirm that HB and barrier-to-autointegration factor are the same protein.
authors.affiliation: Department of Immunology, Hospital de Sant Pau, Universitat Autonoma de Barcelona, Barcelona, Spain.
authors.forename: Ignasi
authors.initials: I
authors.lastname: Forné
authors.forename: Montserrat
authors.initials: M
authors.lastname: Carrascal
authors.forename: Luis
authors.initials: L
authors.lastname: Martinez-Lostao
authors.forename: Joaquin
authors.initials: J
authors.lastname: Abian
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Rodriguez-Sánchez
authors.forename: Candido
authors.initials: C
authors.lastname: Juarez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens / Q000737:chemistry / Q000502:physiology*; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000502:physiology*; D019992:Databases as Topic; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D008099:Liver / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry / Q000502:physiology*; D011485:Protein Binding; D016622:Silver Staining; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin / Q000494:pharmacology
chemical_list: D001324:Autoantigens; C501959:BANF1 protein, human; C501960:Banf1 protein, mouse; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D004247:DNA; D014357:Trypsin