title: Interaction between transactivation domain of p53 and middle part of TBP-like protein (TLP) is involved in TLP-stimulated and p53-activated transcription from the p21 upstream promoter.
abstract: TBP-like protein (TLP) is involved in transcriptional activation of an upstream promoter of the human p21 gene. TLP binds to p53 and facilitates p53-activated transcription from the upstream promoter. In this study, we clarified that in vitro affinity between TLP and p53 is about one-third of that between TBP and p53. Extensive mutation analyses revealed that the TLP-stimulated function resides in transcription activating domain 1 (TAD1) in the N-terminus of p53. Among the mutants, #22.23, which has two amino acid substitutions in TAD1, exhibited a typical mutant phenotype. Moreover, #22.23 exhibited the strongest mutant phenotype for TLP-binding ability. It is thus thought that TLP-stimulated and p53-dependent transcriptional activation is involved in TAD1 binding of TLP. #22.23 had a decreased transcriptional activation function, especially for the upstream promoter of the endogenous p21 gene, compared with wild-type p53. This mutant did not facilitate p53-dependent growth repression and etoposide-mediated cell-death as wild-type p53 does. Moreover, mutation analysis revealed that middle part of TLP, which is requited for p53 binding, is involved in TLP-stimulated and p53-dependent promoter activation and cell growth repression. These results suggest that activation of the p21 upstream promoter is mediated by interaction between specific regions of TLP and p53.
authors.affiliation: Department of Biology, Graduate School of Science, Chiba University, Chiba, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Maeda
authors.affiliation: Department of Biology, Graduate School of Science, Chiba University, Chiba, Japan.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Biology, Graduate School of Science, Chiba University, Chiba, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Biology, Graduate School of Science, Chiba University, Chiba, Japan.
authors.forename: Taka-aki
authors.initials: TA
authors.lastname: Tamura
mesh_terms: D001483:Base Sequence; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D034741:RNA, Small Interfering; D020133:Reverse Transcriptase Polymerase Chain Reaction; D035182:TATA Box Binding Protein-Like Proteins / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000378:metabolism*
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D034741:RNA, Small Interfering; D035182:TATA Box Binding Protein-Like Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53