Chromosomal Fragile Site FRA16D tumor suppressor gene Wwox contributes to aerobic metabolism and oxidative stress response. Drosophila melanogaster

The WWOX gene spans chromosomal fragile site FRA16D, a region of DNA instability in cancer. While WWOX has some tumor suppressor characteristics, its normal role and functional contribution to cancer are unclear. Drosophila homozygous Wwox mutants are viable with no discernable phenotype. Drosophila Wwox interactors, identified by proteomics and micro-array analyses, mainly have roles in aerobic metabolism. Functional relationships between Wwox and either isocitrate dehydrogenase (IDH) or superoxide dismutase 1 (Sod1) were confirmed by phenotype modification, including Sod1 ‘crinkled-wing’, indicative of oxidative stress response. Endogenous reactive oxygen species levels reflect Wwox levels in Drosophila. WWOX mRNA levels in Drosophila and human cells correlate with IDH and Sod1 levels. Wwox therefore contributes to pathways involving glucose metabolism and oxidative stress response. Overall design: Drosophila embryos were harvested between 4-8hrs and total RNA isolated to look for gene-expression differences induced by the presence of one of two altered Wwox alleles relative to wild-type. The two alleles were Wwox (a null mutation generated by homologous recombination) and Wwoxf04545 carrying a pBac insertion in exon 2 (O’Keefe et al., 2005, 2007). Embryo pools were isolated in triplicate, providing 3 biological replicates.