Figure 7.—

moleskin/dim-7 dominantly suppresses ectopic bristle formation and reduces ectopic Sens expression. Df pbl-X1 uncovers moleskin/dim-7 and was identified as a dominant suppressor of the ls phenotype (compare A and D with Figure 1, D and E). A previously identified mutation in msk (msk⁵) fails to complement the deficiency (data not shown) and also suppresses the ls phenotype (B and E). Fifteen EMS mutants were identified as alleles of msk; these also suppress the ls phenotype (C and F and data not shown). Consistent with this observation, ectopic expression of Sens in 48-hr APF discs heterozygous for msk⁵ (+/−) is reduced compared to that in the wild-type twinspot (+/+) (G–I). G shows GFP staining in green. The twinspot boundary is outlined in white. Sens staining is shown in red (H). To illustrate the differences in Sens staining between the twinspot and heterozygous tissue, pixel intensity from H was mapped to a heat scale (I); dim pixels are dark blue and bright pixels are yellow. Genotype of (+/+) is ls/+; ubi-GFP, FRT80B/ubi-GFP, FRT80B. Genotype of (+/−) is ls/+; ubi-GFP, FRT80B/msk⁵, FRT80B.