Fig. 2. tlr loss-of-function phenotype in the embryonic CNS. (A) tlr^ex[2-41]/tlr^E1 embryos overall have a normal CNS appearance when stained with mAb BP102. Staining with anti-Fas2 antibody reveals defects in the CNS (B-D) and motoneuron arbors (F-L). Red arrows indicate defects; black arrows indicate normal projections. The CNS fasciculation defects (red arrows) vary from mild (C) to severe (B,D). (E) Schematic of the wild-type motoneuron projections, adapted from Landgraf et al. (Landgraf et al., 1997). (F-L) tlr^ex[2-41]/tlr^E1 embryos showed a variety of guidance defects (red arrows; black arrows indicate wild-type-like projections): (F) delay in ISN growth and (G) defective ISN terminal arbor morphology; (H) SNa stalling and (I) additional branching; (L) SNb failure to reach ventral muscle targets. Schematic diagrams illustrate SNa and SNb stalling (J) and misguidance (K) in tlr mutants. (M-S) Innervation on ventral muscles in third-instar larvae visualized with anti-Fas2 antibody (M-O) or anti-csp antibody (P-S). Dorsal is up and anterior is left in all except B which is a view from ventral side. Scale bars are 50 µm in B,G,I,L; 100 µm in O,S.