Figure 4.

Transcriptional regulation of Tor, hyx, and Thor in fly. Heterozygous Tor^+/− (Tor^MB07988/+) and homozygous Tor^−/− (Tor^{MB07988/MB07988}) mutant flies have a dose-dependent reduction in both Tor and hyx transcript compared with w¹¹¹⁸ controls (a and b). Heterozygous hyx (hyx^EY6898/+) mutant flies show a reduction in hyx, but not in Tor transcript expression (a and b). Thor/4E-BP transcript expression is significantly reduced in hyx/CDC73^+/− flies compared with w¹¹¹⁸ controls, and is rescued back to control levels following act5C-GAL4-driven overexpression of hyx/CDC73 from the hyx^EY6898 allele (c). The act5C-GAL4/+ driver alone has no effect on Thor/4E-BP transcript levels (d). Tor^+/− heterozygosity and Tor^+/−;hyx^+/− double heterozygosity results in a decrease in Thor/4E-BP transcript levels, and is similarly rescued following act5C-GAL4-driven overexpression of hyx/CDC73 from the hyx^EY6898 allele in the Tor^+/−;hyx^+/− double heterozygous mutant background (e). Heterozygosity of hyx/CDC73^+/− has no effect on transcript levels of s6k/RPS6KB1, which is, like 4E-BP, a major effector of Tor (f). For a, b, c, and e ^**P<0.005; ^***P<0.0005 compared with w¹¹¹⁸ control, using unpaired Student's t-test