Figure 3.

Effects of the combination of Hipp^Δ1and mod(mdg4)^u1 mutations on gypsy enhancer blocking activity. (a) Scheme (not to scale) of the y² allele. Exons in the yellow gene are shown as white rectangles; the yellow wing (En-w) and body (En-b) enhancers are shown as partially overlapping gray boxes; the bristle enhancer (En-br) is shown as a gray oval in the yellow intron. The transcription start site is indicated by an arrowhead. The gypsy insertion is shown as a triangle, in which the black circle marked Gy is the gypsy insulator and the white boxes are long terminal repeats, with arrows indicating their directions. (b) Images show the effects of the mod(mdg4)^u1/mod(mdg4)^u1 − [mod⁻], Hipp^Δ1/Hipp^Δ1 − [HIPP1⁻], and Hipp^Δ1mod(mdg4)^u1/Hipp^Δ1mod(mdg4)^u1 − [HIPP1⁻ mod⁻] mutants on the yellow phenotype and on abdomen pigmentation in three-day-old y² males. The term “wt” refers to the wild type. Numbers show the yellow expression scores in the abdominal segments (5, maximal pigmentation; 2, weak pigmentation; var, variegated pigmentation; 4, moderate pigmentation). (c) Quantitative assessment of the pigmentation intensity of the abdominal A5 segments. Images were analysed using the Measure tool in Fiji. “Mean” parameters were used for histogram generation. For each genotype, 20 representative images were processed. Pigmentation intensity (Y axis) is shown as fold change relative to the y² variant. Error bars indicate standard deviation of pigmentation intensity. Asterisks indicate significance levels (Student’s t-test) of **p < 0.01. Statistical analysis was performed relative to the y² variant.