Figure 3.

mnm expression. (A) RNA gel blot, stages as indicated. mnm mRNA is indicated by an arrowhead. (B) RT gel. RNA from single embryos was isolated and analyzed by RT–PCR using gene-specific mnm primers. The arrowheads mark the predicted RT product in all sections. The top band in all sections is the predicted product from genomic DNA remaining in the reaction. Genotypes are mnm¹/CyO and mnm¹ (top), mnm^P/CyO and mnm^P (middle), and mnm^PX1/CyO and mnm^PX1 (bottom). There was no detectable transcript in mnm^P or mnm^PX1 homozygote embryos compared to the heterozygote controls (middle and bottom sections). The mnm transcript appeared to be overexpressed in the mnm¹ homozygote embryos compared to controls (top), suggesting that mnm¹ may be a hypermorphic or neomorphic allele. (C–F) RNA in situ hybridization experiments: (C) glass antisense, (D) glass sense, (E) mnm antisense, and (F) mnm sense. Third instar eye-imaginal discs: anterior right, to the same scale indicated in F. The morphogenetic furrow is indicated by an arrowhead. Note the elevated expression of mnm mRNA in the eye field and in parts of the antenna (arrows in E).