TRANSACTIVATION BY THE DROSOPHILA MYB GENE-PRODUCT REQUIRES A DROSOPHILA HOMOLOG OF CBP

Attempts to demonstrate trans-activation activity by the Drosophila my b gene product (D-Myb) have been unsuccessful so far. We demonstrate t hat co-transfection of Schneider cells with a plasmid expressing the D rosophila homologue of transcriptional co-activator CBP (dCBP) results in transactivation by D-Myb. Using this assay system, the functional domains of D-Myb were analyzed. Two domains located in the N-proximal region, one of which is required for DNA binding and the other for dCB P binding, are both necessary and sufficient for trans-activation. In this respect, D-Myb is similar to c-Myb and A-Myb, but different from mammalian B-Myb. These results shed light on how the myb gene diverged during the course of evolution. (C) 1997 Federation of European Bioch emical Societies.