Fig. 2. Reporter gene expression phenotype in the wild-type Drosophila embryonic brain. Characterization of brain-specific lab::Gal4 driver K5J2 using P{w+; lab::Gal4}K5J2-driven UAS::taulacZ reporter gene expression (Callahan and Thomas, 1994). Laser confocal microscopy of stage 15 embryos, reconstructions of optical sections. (A,C) Frontal views; (B) lateral view; (D) midline cross-section. (A,B,D) Double immunolabeling with anti-HRP (red) and anti-ß-gal (green). P{w+ lab::Gal4}K5J2-driven UAS::taulacZ reporter gene expression is seen in the cortical cytoskeleton and axons of cells in the endogenous tritocerebral Lab expression domain (arrows in A,B) of the wild-type embryonic brain. Arrowhead indicates tritocerebral commissure. Ectopic reporter gene expression is seen in a small number of cells in the deutocerebral and mandibular neuromeres. (C) Double immunolabeling with anti-Lab (red) and anti-ß-gal (green) shows that reporter gene expression occurs in the cortical cytoskeleton of the cells that also show nuclear Lab expression (arrows in C) as well as in their axons projecting along the tritocerebral commissure (arrowhead indicates the tritocerebral commissure). (D) Reporter gene expression is seen in the midline cross-section of the tritocerebral commissure (arrow).
