Fig. 9

Analysis of hbn enhancer gene targeting strains. A-F Laser confocal images of stage 16 embryonic brains from the different hbn enhancer targeting strains compared to a wild-type brain stained with antibodies against HRP (green) and Hbn (red). In the wild-type brain, the supraesophageal commissure (SEC) and the protocerebral connectives (PCN) are the most prominent structures visible (A), but the sizes of these structures are reduced in all the hbn enhancer gene targeting strains (B-F). A Hbn is expressed in the medial region (red arrowhead), central region (white arrowhead), lateral region (yellow arrowhead) and in close association with the commissure (magenta arrowhead). B In strain 35D05^KO, Hbn expression is reduced in the medial and central regions (blue arrowheads). C Strain 34G10^KO shows reduced Hbn expression again in the medial and central regions (blue arrowheads). D In strain 35A03^KO, Hbn expression in the central and lateral regions is substantially reduced (blue arrowheads). E Strain 34G10,35A03^KO shows the most dramatic phenotype with the most substantial decreases in the sizes of the commissure and PCNs. Hbn expression is almost completely absent in the medial and central regions (blue arrowheads), and the brain size is smaller. F Strain hbn3’^KO shows a slight reduction in Hbn expression in the medial, central and lateral regions. G, H Laser confocal images of right hemispheres from third instar larval brains stained with Nrt (green) and Hbn (red) antibodies. G In the wild-type optic lobe, Hbn is expressed in the lobula plate (LP) (white arrowhead). H In the 35A03^KO strain, Hbn expression in the lobula plate is not observed (blue arrowhead). Abbreviations are indicated in the figure. (Scale bars: A-F, 25 μm; G, H, 50 μm)