Fig. 2. Mutant brain phenotype observed in vnd-null mutant embryos at embryonic stage 15. Laser confocal microscopy reconstructions of optical sections, lateral views. (A,B) Double-immunolabelling with anti-HRP antibody (red) and anti-ELAV antibody (yellow/green). (C,D) Double-immunolabelling with anti-HRP antibody (red) and glial-specific anti-REPO antibody (yellow/green). Arrows indicate general trito-deutocerebral region. (E,F) Double immunolabelling with anti-HRP antibody (red) and an anti-EN antibody (yellow/green). (A) In wild type, neuron-specific marker ELAV reveals all neural cell bodies. (B) By contrast, in vnd-null mutants a large gap is seen in the tritocerebral/deuterocerebral region (arrow). (C) The glia-specific marker REPO reveals localization of glial cell bodies in embryonic wild-type brain. (D) In vnd mutant embryos, REPO-expressing cells in residual tritocerebral/deuterocerebral region appear to be present but are severely misplaced (arrow). (E) In wild type, the protocerebral b1 en-stripe (b1), deuterocerebral b2 en-stripe (b2), tritocerebral b3 en-stripe and anteriormost en expressing secondary head spot (shs) are visible (arrowheads). (F) By contrast, in vnd-null mutant embryos only b1 en-stripe and en expressing secondary head spot are present (arrowheads), and neuron-specific HRP marker reveals a cellular gap in deuto- and tritocerebral region (arrow).