c-Myb Regulates the Cell Cycle

    Monoblasts transformed by v-myb can be induced to differentiate by treatment with the phorbol ester TPA. During this process, the cells exit the cycle in both the G1 and G2 phases. Expression of a protein consisting only of the three repeats of c-Myb (3R) can prevent both the TPA-induced differentiation and cell cycle arrest. This was a surprising result because the 3R protein had been shown to function as a "dominant negative" inhibitor of transcriptional activation by both v-Myb and c-Myb in transient assays. These results suggest that the c-Myb DNA-binding domain can control the cell cycle even in the absence of a transcriptional activation domain.

Dini and Lipsick, Molec Cell Biol 13: 7334-7348 (1993).

Engelke, Smarda, and Lipsick, Oncogene 11: 735-741 (1995).