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

• Published in: PloS one 2014-03, Vol.9 (3), p.e90190-e90190
• Main Authors: Maeda, Ryo, Suzuki, Hidefumi, Tanaka, Yuta, Tamura, Taka-aki
• Format: Article
• Language: English
• Subjects: Amino acids; Analysis; Apoptosis; Base Sequence; Biology; Cell activation; Cell death; Cell Line, Tumor; Cyclin-dependent kinase inhibitor p21; Cyclin-Dependent Kinase Inhibitor p21 - metabolism; Deoxyribonucleic acid; DNA; DNA repair; Etoposide; Gene expression; GTP-binding protein; Humans; Kinases; Medicine; Mutagenesis; Mutants; Mutation; N-Terminus; p53 Protein; Plasmids; Promoter Regions, Genetic; Protein Binding; Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; TATA Box Binding Protein-Like Proteins - genetics; TATA Box Binding Protein-Like Proteins - metabolism; Transcription (Genetics); Transcription activation; Transcription factors; Transcription, Genetic; Transcriptional Activation; Tumor proteins; Tumor Suppressor Protein p53 - chemistry; Tumor Suppressor Protein p53 - metabolism
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0090190

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.