title: TdIF2 is a nucleolar protein that promotes rRNA gene promoter activity.
abstract: Terminal deoxynucleotidyltransferase (TdT) interacting factor 2 (TdIF2) is an acidic protein that binds to TdT. TdIF2 binds to DNA and core histones and contains an acidic-amino acid-rich region in its C-terminus. It has therefore been suggested to function as a histone chaperone within the nucleus. TdIF2 localized within the nucleolus in HEK 293T cells, and its N-terminal (residues 1-234) and C-terminal (residues 606-756) regions were crucial for the nucleolar localization. A chromatin immunoprecipitation (ChIP) assay showed that TdIF2 associated with the promoter of human ribosomal RNA genes (hrDNAP), and an in vitro luciferase assay system showed that it promoted hrDNAP activity. Using the yeast two-hybrid system with TdIF2 as the bait, we isolated the cDNA encoding HIV Tat interactive protein 60 (Tip60), which has histone acetyltransferase (HAT) activity, as a TdIF2-binding protein. TdIF2 bound to Tip60 in vitro and in vivo, inhibited the Tip60 HAT activity in vitro and co-localized with Tip60 within the nucleolus. In addition, TdIF2 promotes upstream binding factor (UBF) acetylation in vivo. Thus, TdIF2 might promote hrDNAP activity by suppressing Tip60's HAT activity and promoting UBF acetylation.
authors.affiliation: Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba, Japan. koiwaitm@rs.noda.tus.ac.jp
authors.forename: Kotaro
authors.initials: K
authors.lastname: Koiwai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Noma
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Takahide
authors.initials: T
authors.lastname: Hayano
authors.forename: So
authors.initials: S
authors.lastname: Maezawa
authors.forename: Kousuke
authors.initials: K
authors.lastname: Kouda
authors.forename: Takuro
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Suzuki
authors.forename: Masaki
authors.initials: M
authors.lastname: Furuichi
authors.forename: Osamu
authors.initials: O
authors.lastname: Koiwai
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002466:Cell Nucleolus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism; D015536:Down-Regulation; D057809:HEK293 Cells; D051548:Histone Acetyltransferases / Q000378:metabolism; D006801:Humans; D000074443:Lysine Acetyltransferase 5; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D021381:Protein Transport; D012335:RNA, Ribosomal / Q000235:genetics*; D016601:RNA-Binding Proteins; D016415:Sequence Alignment; D020798:Two-Hybrid System Techniques
chemical_list: D002352:Carrier Proteins; C484899:DNTTIP2 protein, human; D009687:Nuclear Proteins; D012335:RNA, Ribosomal; D016601:RNA-Binding Proteins; D051548:Histone Acetyltransferases; C098489:KAT5 protein, human; D000074443:Lysine Acetyltransferase 5; D004253:DNA Nucleotidylexotransferase