Figure 15. Ultrastructure of BAG and FLP cilia.
(A) 3D reconstruction model of BAG (purple) and FLP (green) sensory endings. BAG and FLP sensory endings are positioned laterally. FLP has an extensive dendritic branching network. Scale bar: 1 µm. (B and B′) 3D reconstruction models of BAG and FLP endings indicating TZs (gray). BAG and FLP (transparent) closely ensheath the ending of the ILso glial cell (yellow-tan). Approximate locations of sections shown in C–J are indicated. Arrowheads indicate bulbous structures in FLP dendritic branch. (C) Cross-section TEM image showing the far distal end of BAG cilium with several dMTs (inset) at the edges of the BAG ciliary branches (black arrows) and associating with the ILso process. (D) The distal segment of the BAG cilium wraps around a projection of the ILso and contains dMTs (inset) segregating preferentially to one side. (E and F) Ultrastructures of the BAG TZ (E) and rootlet (arrowhead in F). (G) The distal segment of FLP cilia has flap-like projections with several dMTs (arrow). (H) The middle segment of FLP cilia contains several disorganized dMTs. (I) The FLP TZ contains nine dMTs. (J) Arrowhead indicates rootlet-like structures in the FLP PCMC. (K) Longitudinal ET view of a FLP dendritic branch shows an iteratively bulbous dendrite (arrows) that includes 2–3 MTs, which are tightly packed in the ∼60 nm constrictions between bulbs (inset). Scale bars: 100 nm.