Figure 5.

Disruption in the chordotonal organ (CO) morphology and BNB function in nrx IV, cont, and nrg mutants. (a) Schematic of a CO showing the various cell types. Cap cells (cc, green), scolopale (sc, red), and ligament (lig) are the three glial cell types. The neuron (neu, blue) has a rootlet (r) and its dendrite (d) projects into the lumen (lu) of the scolopale. The cc and the lig cell attachment sites of the CO to the epidermis (ep) are also shown. The presence of extensive SJs is apparent between the cap and scolopale cells, thus providing a functional BNB. (b) Wild-type CO triple stained with antiβ3tubulin (green) marking the cap cells, anti-Crb (red) marking the lumen of the scolopale, and anti22C10 (blue) marking the sensory neuron. (c–h) Wild-type COs (c, e, and g) stained with anti-CRB (red) and anti22C10 (blue) in combination with anti-Nrx IV (c, d), anti-Cont (e, f), and anti-Nrg (g–h) show a fusiform shape of the scolopales in the CO cluster. nrx IV (d), cont (f), and nrg (h) mutants as evident from the lack of staining of their respective antibodies show a defective morphology and a disarrayed organization of the cluster. (i–l) Dye exclusion assays performed on the wild-type embryos (i), nrx IV (j), cont (k) and nrg (l) mutant embryos. Confocal images after dye injection of the regions of the peripheral nervous system at the level of the COs. Wild-type embryos (i) excluded the dye from the COs even after 30 min of injection, indicating that a functional BNB is present. Under identical conditions nrx IV (j), cont (k), and nrg (l) mutant embryos failed to exclude the dye from the COs. Confocal images showed dye penetration into COs within 15 min after injection, indicating that the BNB has broken down in these mutants. Printed with permission from Banerjee et al. (2006a); copyright 2006 by the Society for Neuroscience.