Drosophila myb may play a role in regulating differentiation as well as proliferation during development. C.A. Fitzpatrick , N. Sharkov , A.L. Katzen. Molecular Genetics, Univ Illinois, Chicago, IL.
Drosophila myb (Dm myb) encodes a transcription factor and is related to the vertebrate proto-oncogene, c-myb. Based on our analysis of partial loss of function mutations, we have previously shown that myb is essential for viability and is required for progression through the G2/M transition, as well as suppression of endoreduplication in at least some cell types. To further understand the physiological roles of Dm myb during development, we are using the Gal4/UAS system to investigate the consequences of ectopic expression of wild-type and mutant constructs carrying the full-length Dm myb gene, full-length myb fused to GFP and an overly active version of myb (similiar to the oncogenic version in vertebrates). We have successfully generated these transgenic lines and have mated them to a variety of Gal4 driver lines. Our results demonstrate that ectopic expression of full-length Dm myb within the developing animal can have potent consequences. It can induce lethality and disrupt patterning in the wing. The activated version of Dm myb can also suppress endoreduplication in salivary glands, disturb eye development, and disrupt cell-cycle regulation in the wing. These findings indicate that in addition to being required for cell proliferation, Dm myb plays a key role in regulating some differentiation pathways during imaginal development.