The leukemia-associated protein Btg1 and the p53-regulated protein Btg2 interact with the homeoprotein Hoxb9 and enhance its transcriptional activation.
BTG1 and BTG2 belong to a family of functionally related genes involved in the control of the cell cycle. As part of an ongoing attempt to understand their biological functions, we used a yeast two-hybrid screening to look for possible functional partners of Btg1 and Btg2. Here we report the physical and functional association between these proteins and the homeodomain protein Hoxb9. We further show that Btg1 and Btg2 enhance Hoxb9-mediated transcription in transfected cells, and we report the formation of a Hoxb9.Btg2 complex on a Hoxb9-responsive target, and the fact that this interaction facilitates the binding of Hoxb9 to DNA. The transcriptional activity of the Hoxb9.Btg complex is essentially dependent on the activation domain of Hoxb9, located in the N-terminal portion of the protein. Our data indicate that Btg1 and Btg2 act as transcriptional cofactors of the Hoxb9 protein, and suggest that this interaction may mediate their antiproliferative function.
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Unité INSERM U453, Centre Léon Bérard, 69373 Lyon Cedex 08, France.
Voeltzel
T
T
Birot
A M
AM
Morel
A P
AP
Rostan
M C
MC
Magaud
J P
JP
Corbo
L
L
D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000378:metabolism*; D016147:Genes, Tumor Suppressor; D006131:Growth Inhibitors; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D017874:Immediate-Early Proteins / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques
C489552:Btg1 protein, mouse; C489435:Btg2 protein, mouse; D004268:DNA-Binding Proteins; D006131:Growth Inhibitors; C491257:HOXB9 protein, human; D018398:Homeodomain Proteins; D017874:Immediate-Early Proteins; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins