TATA binding protein associated factor 3 (TAF3) interacts with p53 and inhibits its function.
BACKGROUND
The tumour suppressor protein p53 is a sequence specific DNA-binding transcription regulator, which exerts its versatile roles in genome protection and apoptosis by affecting the expression of a large number of genes. In an attempt to obtain a better understanding of the mechanisms by which p53 transcription function is regulated, we studied p53 interactions.


RESULTS
We identified BIP2 (Bric-à-brac interacting protein 2), the fly homolog of TAF3, a histone fold and a plant homeodomain containing subunit of TFIID, as an interacting partner of Drosophila melanogaster p53 (Dmp53). We detected physical interaction between the C terminus of Dmp53 and the central region of TAF3 both in yeast two hybrid assays and in vitro. Interestingly, DmTAF3 can also interact with human p53, and mammalian TAF3 can bind to both Dmp53 and human p53. This evolutionarily conserved interaction is functionally significant, since elevated TAF3 expression severely and selectively inhibits transcription activation by p53 in human cell lines, and it decreases the level of the p53 protein as well.


CONCLUSIONS
We identified TAF3 as an evolutionarily conserved negative regulator of p53 transcription activation function.
Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary. opszin@gmail.com
Orsolya
O
Bereczki
Zsuzsanna
Z
Ujfaludi
Norbert
N
Pardi
Zita
Z
Nagy
Laszlo
L
Tora
Imre M
IM
Boros
Eva
E
Balint
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D045744:Cell Line, Tumor; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D008954:Models, Biological; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018411:Spodoptera; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
C432688:BIP2 protein, Drosophila; D029721:Drosophila Proteins; C432689:TAF3 protein, human; D035381:TATA-Binding Protein Associated Factors; D035362:Transcription Factor TFIID; D016159:Tumor Suppressor Protein p53