Figure 4.

Dynamics of axonemal MTs at the middle segment and distal segment tips. (a–c) Cilia expressing TBB-4::YFP were photobleached in different regions and recovery was recorded for entire cilia (a), tips of middle segments (b) and distal segments (c) in phasmids. In each case, images are shown before, at (0 s) and after photobleaching. The arrows point to the recovery regions. The cartoon at the upper left for each set represents the region of cilia that was analyzed; the photobleached region is shown by a black square and the region used for recovery analysis is shown by a red square. Bar=5 μm. (d–e) The kinetics of FRAP recovery at the tips of middle segments (d) and the distal segments (e) were fit with a single exponential equation (red line). The fluorescence intensity is normalized to the prebleach. (f) EBP-2::GFP proteins are more concentrated at the tips of middle segments and distal segments. Bar=5 μm. (g) A line scan along the cilia in (f) is shown. (h) Dynamics of EBP-2::GFP in dendrites where the EB1 homolog tracks the tips of the MTs. The arrows point to the comets. Bar=5 μm. (i) A kymograph of EBP-2::GFP comets from (h) is shown. Horizontal bar=10 μm and vertical bar=10 s. The labels are: BB, basal body (equivalent to TZ); CB, cell Body; D, dendrite; DS, distal segment; MS, middle segment; TZ, transition zone.