The myb-related gene stonewall induces both hyperplasia and cell death in Drosophila: Rescue of fly lethality by coexpression of apoptosis inducers

Abstract

We carried out gain-of-function mutagenesis screening and identified a mutant in which GAL4 induction led to both hyperplasia and apoptosis. The gene involved was identified as stonewall (stwl), a myb-related gene involved in germ cell proliferation and differentiation during oogenesis. As observed with dmyb, the ectopic expression of stwlUY823 inhibited endoreplication in salivary glands. We also found that stwlUY823 overexpression, like overexpression of the wild-type gene, activated G1/S transition and apoptosis. The apoptosis triggered by stwlUY823 expression is correlated to induction of the proapoptotic gene reaper. Finally, the death of flies induced by ectopic stwlUY823 expression is efficiently prevented in vivo by triggering cell death in stwlUY823 -expressing cells. Our results suggest that stwlUY823 kills flies by causing inappropriate cell cycle entry, and that triggering the death of these overproliferating cells or slowing their proliferation restores viability. © 2006 Nature Publishing Group. All rights reserved.