Interaction between the hematopoietic Ets transcription factor Spi-B and the coactivator CREB-binding protein associated with negative cross-talk with c-Myb.
We have previously shown that the hematopoietic Ets transcription factor PU.1 interacts with the transcriptional coactivator CREB-binding protein (CBP). In this study, we further investigated whether Spi-B, another hematopoietic Ets transcription factor, also interacts with CBP. Direct physical interaction of Spi-B with CBP was demonstrated by glutathione S-transferase binding assay. Analysis using several deletion mutants of Spi-B and CBP revealed that the NH2-terminal region including the activation domain of Spi-B interacted with the region spanning amino acid residues 1283-1915 of CBP in vitro. The interaction of Spi-B with CBP was also observed in vivo. CBP potentiated Spi-B-mediated transcription of the reporter gene driven by the multimerized PU.1/Spi-B binding sites. This transcriptional activation by Spi-B and CBP was inhibited by expression of c-Myb, and the transcriptional activation by c-Myb and CBP was inhibited by expression of Spi-B, suggesting competition for CBP between these two transcription factors. Our results suggest that CBP acts as a transcriptional coactivator of Spi-B and mediates synergistic or antagonistic interactions between other transcription factors.
Yamamoto
Hitomi
H
Department of Cell Genetics, Sasaki Institute, Tokyo 101-0062, Japan.
Kihara-Negishi
Fumiko
F
Yamada
Toshiyuki
T
Suzuki
Mitsuhiro
M
Nakano
Tohru
T
Oikawa
Tsuneyuki
T
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D050882:CREB-Binding Protein; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015536:Down-Regulation; D005982:Glutathione Transferase / Q000378:metabolism; D006410:Hematopoiesis; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism*; D009842:Oligopeptides; D010455:Peptides; D010957:Plasmids; D011233:Precipitin Tests; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D000099232:Proto-Oncogene Protein Spi-1
D000123:Acetyltransferases; D050882:CREB-Binding Protein; D004268:DNA-Binding Proteins; D005982:Glutathione Transferase; D008156:Luciferases; D009687:Nuclear Proteins; D009842:Oligopeptides; D010455:Peptides; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D015534:Trans-Activators; D014157:Transcription Factors; D000099232:Proto-Oncogene Protein Spi-1; C076877:SPIB protein, human; C085706:FLAG peptide; C494363:CREBBP protein, human; C494364:Crebbp protein, mouse