The V-Myb Oncogene

The v-myb oncogenes, the oncogenic components of two different avian leukaemia viruses, encode proteins that are mutated and truncated versions of c-Myb. Although derived from chicken c-myb gene, the biological effects of v-Myb are strikingly different from that of c-Myb. While c-Myb is essential for haemopoietic development, overexpression of v-Myb transforms cytokinedependent immature haemopoietic cells in culture and induces acute leukaemias in animals. This has led to the speculation that v-Myb specific mutations and truncations unmask the normally latent transforming activity of c-Myb. In this chapter, we critically review some important aspects of v-Myb including its transforming activities, haemopoietic specificity and the structure and function of the oncoprotein. Our analysis will emphasise the molecular mechanisms of how v-Myb specific mutations and truncations lead to its oncogenic activation.