Figure 4

Temperature dependence of the GAL4/UAS system in Tribolium. The transactivator line Tc-hsp-GAL4Δ#1 was crossed to the responder line UAS-Tc-bhsp-tGFP#7. Eggs from a 1h collection were heat shocked and checked for tGFP fluorescence directly after heat shock, at five one-hour intervals, and again after 24h. Each row shows the same embryos at a given time after heat shock kept at a certain temperature. As both lines are heterozygous, only about 25% of embryos were expected to exhibit tGFP fluorescence. In the bottom row, embryos of the heat shocked responder line at 30°C are shown as negative control. At 26°C, fluorescence is first seen 5 hours after heat shock (Af); at 28°C: 4-5 hours (Be; Bf); at 30°C: 3-4 hours (Cd; Ce); at32°C: 3 hours (Dd).