Figure 1.

hsf activity is likely to participate in tll repression. (A–D) tll mRNA patterns in embryos at early stage 4 (A and C) and stage 5 (B and D) were determined by in situ hybridization with a digoxigenin-labeled antisense tll RNA. w¹¹¹⁸ embryos were incubated at either 25 (A and B) or 29°C (C and D). Embryos are arranged in a sagittal view, with the anterior towards the left. (E–H) lacZ protein distribution in embryos from G11 (E and G) or hsf⁴; G11 (F and H) parents was determined by X-gal staining. The heat-shock treatment (hs) was at 37°C for 30 min (G and H). G11 embryos serve as controls (E and G). Embryos at early stage 5 are shown, with the anterior towards the left.