Transcriptional autorepression of Msx1 gene is mediated by interactions of Msx1 protein with a multi-protein transcriptional complex containing TATA-binding protein, Sp1 and cAMP-response-element-binding protein-binding protein (CBP/p300)

• Published in: Biochemical journal Vol. 339; no. 3; pp. 751 - 758
• Main Authors: SHETTY, Sheetal, TAKAHASHI, Takayuki, MATSUI, Hideo, AYENGAR, Rekha, RAGHOW, Rajendra
• Format: Journal Article
• Language: English
• Published: England 01.05.1999
• Subjects: Animals; Cell Line; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Down-Regulation; Histone Acetyltransferases; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Mice; Msx1 gene; Msx1 protein; MSX1 Transcription Factor; Nuclear Receptor Coactivator 3; Precipitin Tests; Promoter Regions, Genetic - genetics; Protein Binding; Repressor Proteins - genetics; Repressor Proteins - metabolism; Response Elements - genetics; Sequence Deletion; Sp1 Transcription Factor - genetics; Sp1 Transcription Factor - metabolism; TATA-Box Binding Protein; Trans-Activators - genetics; Trans-Activators - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic - genetics; Transfection; Tumor Cells, Cultured
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/0264-6021:3390751

The TATA-less murine Msx1 promoter contains two Msx1-binding motifs, located at -568 to -573 and +25 to +30, and is subject to potent autorepression [Takahashi, Guron, Shetty, Matsui and Raghow (1997) J. Biol. Chem. 272, 22667-22678]. To investigate the molecular mechanism by which Msx1 represses the activity of its own promoter, we transfected C2C12 myoblasts with Msx1-promoter-luciferase constructs and assessed reporter gene activity, with and without the exogenous expression of Msx1. We demonstrate that Msx1-mediated autorepression remained unaffected, regardless of the presence or absence of the Msx1 recognition motifs on the promoter. Furthermore, graded exogenous expression of TATA-binding protein (TBP), Sp1 or cAMP-response-element-binding protein-binding protein (CBP/p300) could counteract the autoinhibitory activity of Msx1. Finally, we demonstrate that Msx1 protein can be immunoprecipitated in a multiprotein complex containing TBP, Sp1 and CBP/p300. We hypothesize that the interaction of Msx1 protein with one or more ubiquitous or tissue-restricted transcription factors mediates transcriptional autorepression of the Msx1 gene.