Figure 5.

Reduced expression of the Draf–lacZ gene in embryos homozygous for the dE2F mutation. The w/w; Draf-lacZ/Draf-lacZ; E2F⁷¹⁷²/TM3 line was made through genetic crossing of E2F⁷¹⁷²/TM3 flies with transgenic flies carrying p5′-663Drafwt-lacZ, which contains the DNA fragment from the D-raf promoter region (–663 to +302) fuzed to lacZ (12). Expression patterns of Draf–lacZ in wild-type (A) and homozygous dE2F mutant embryos (B) were detected by X-gal staining. The embryos are shown at stage 13, the posterior to the left and the dorsal aspect facing upward. Reduced expression of the Draf–lacZ gene in the homozygous dE2F mutant embryo (B) is apparent all over the region. Approximately one-quarter of the stage 13 embryos from parents with the genotype w/w; p5′-663Drafwt-lacZ/p5′-663Drafwt-lacZ; dE2F⁷¹⁷²/TM3 were similar to the embryo shown in (B). (C) Wild-type and E2F⁷¹⁷²/E2F⁷¹⁷² embryos are shown on the same slide. (D) p5′-663Drafwt-lacZ/p5′-663Drafwt-lacZ; +/+ embryos stained homogenously are shown as a control. The embryo in the box shows that the Draf–lacZ expression pattern is essentially identical to the pattern of D-raf transcripts detected by in situ hybridization (13).