Figure 2.

TBCD is required for neuronal morphogenesis of PNs. A, Schematic of the CG7261 gene locus, which encodes the Drosophila ortholog of TBCD. The position of the insertion in TBCD¹ allele is indicated. B, Schematic of tubulin-folding pathway. The cytosolic chaperonin CCT is involved in folding of α- (light gray circle) and β-tubulin (dark gray circle). TBCD interacts with β-tubulin and assists the formation of tubulin heterodimers. Excess TBCD also interacts with tubulin heterodimers and destabilizes microtubules. C, Western analysis of S2 lysates treated with control and TBCD dsRNA and overexpressing TBCD. The anti-TBCD antibody that we generated recognizes a single band with expected size (134 kDa). Expression of TBCD was reduced in the TBCD¹ homozygous mutant embryo. D–G, Images are confocal z-projections. Green indicates morphologies of PNs labeled by mCD8-GFP generated by MARCM using GH146-Gal4. Magenta shows the presynaptic marker Brp. Scale bars, 20 μm. Asterisks and yellow-dotted circles in D, E denote cell bodies of single-cell clones and the DL1 glomerulus, respectively. MB and LH are marked with yellow and white-dotted circles, respectively in F, G. D, F, Dendrites (D) and axon (F) of TBCD¹ mutant DL1 PNs. Arrow in D shows the ectopic dendrite arborization. E, G, Expression of TBCD rescued the defects in the TBCD¹ mutant. H, I, Schematic images of WT (H) and TBCD¹ (I) DL1 single-cell clones. Black arrow in I shows the ectopic dendrite arborization.