CREB-binding proteins (CBP) as a transcriptional coactivator of GATA-2

The GATA family consists of six members, GATA 1-6. In this study, we focused on GATA-2, which is expressed predominantly in hematopoietic progenitor cells and plays the key role in keeping these cells in the undifferentiated status. CREB-binding proteins (CBP) are essential transcriptional coactivators for a large number of regulated DNA-binding transcription factors, including GATA-1. But there have been no reports on whether CBP is still a co-activator of GATA-2. Here, we used the immunoprecipitation and pull-down experiments to show that the GATA-2 and CBP were physically binding together, and clarified the binding sites CH1, CH3, CH452 and CT1430 in CBP and N-finger, C-finger and N-C-finger in GATA-2. Luciferase assay results in our experiment indicated that CBP could increase GATA-2 transcriptional activity in the dose-dependent manner. GATA-1 is mainly expressed in differentiated hematopoietic cells, but still has overlap expression with GATA-2. CBP is a coactivator of GATA-2 and GATA-1. The investigation on the mechanism that could decide whether CBP binds to GATA-2 to keep hematopoietic cells in the progenitor status or to GATA-1 to start differentiation will be a very interesting and very meaningful project in the near future.