Transcriptional activator; DNA-binding protein that specifically recognize the sequence 5'-YAAC[GT]G-3'. Plays an important role in the control of proliferation and differentiation of hematopoietic progenitor cells. Comprised of 3 domains; an N-terminal DNA-binding domain, a centrally located transcriptional activation domain and a C-terminal domain involved in transcriptional repression. Truncation of either the N- or C-terminal of C-Myb leads to increased transformation and transactivation potential.