Cilium-autonomous regulation of tubulin transport by IFT. (A) Schematic presentation of the long-short experiment to generate cells with growing and nongrowing cilia. (B) Bright-field (a), TIRF image (b), and corresponding kymograms (c and d) of a long-short cell. Numerous GFP–α-tubulin transport events (open arrowheads) were observed in the short (S) cilium (d), whereas only a few such events were detected in the long (L) flagellum (c). Bars, 2 µm and 5 s (b and c). (C) Scatter plot of the frequencies of GFP–α-tubulin transport in short (open diamonds) and long (filled diamonds) cilia of long-short cells. (D) The difference in tubulin transport frequencies between the long and the short cilia of given cells diminished as the difference in length between the two cilia decreased (n = 17).