Myb is a transcriptional activator; DNA-binding protein that recognizes the sequence 5'-YAAC[GT]G-3'. It participates in the control of proliferation and differentiation of hematopoietic progenitor cells. Myb is a transcription factor related to Myc, and is expressed predominantly in haematopoietic cells and immature gastroepithelial cells. TRAF7 stimulates the sumoylation of Myb at Lys-523 and Lys-499, which are the same sites as those used for PIASy-induced sumoylation. A correlation has been established between reduction in sumoylation of Myb and increase in transcriptional activation. Negative influence on transactivation properties by the negative regulatory domain region of c-Myb depends on upon sumoylation.