title: TdIF1 recognizes a specific DNA sequence through its Helix-Turn-Helix and AT-hook motifs to regulate gene transcription.
abstract: TdIF1 was originally identified as a protein that directly binds to DNA polymerase TdT. TdIF1 is also thought to function in transcription regulation, because it binds directly to the transcriptional factor TReP-132, and to histone deacetylases HDAC1 and HDAC2. Here we show that TdIF1 recognizes a specific DNA sequence and regulates gene transcription. By constructing TdIF1 mutants, we identify amino acid residues essential for its interaction with DNA. An in vitro DNA selection assay, SELEX, reveals that TdIF1 preferentially binds to the sequence 5'-GNTGCATG-3' following an AT-tract, through its Helix-Turn-Helix and AT-hook motifs. We show that four repeats of this recognition sequence allow TdIF1 to regulate gene transcription in a plasmid-based luciferase reporter assay. We demonstrate that TdIF1 associates with the RAB20 promoter, and RAB20 gene transcription is reduced in TdIF1-knocked-down cells, suggesting that TdIF1 stimulates RAB20 gene transcription.
authors.affiliation: Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kubota
authors.forename: Osamu
authors.initials: O
authors.lastname: Koiwai
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Hori
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Watanabe
authors.forename: Kotaro
authors.initials: K
authors.lastname: Koiwai
mesh_terms: D024761:AT-Hook Motifs / Q000502:physiology*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000737:chemistry* / Q000502:physiology*; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D019077:Helix-Turn-Helix Motifs / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry* / Q000502:physiology*; D011485:Protein Binding; D013379:Substrate Specificity / Q000235:genetics; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000235:genetics; D020691:rab GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C436745:DNTTIP1 protein, human; D009687:Nuclear Proteins; D014157:Transcription Factors; D004247:DNA; C509832:Rab20 protein, human; D020691:rab GTP-Binding Proteins