Fig. 2. The flagellar pocket exhibits a modified shape and accumulates vesicles in IFT^RNAi mutant cells with a short or no flagellum. (A-F) Sections through the flagellar pocket region of wild-type (WT) trypanosomes (A), of the indicated IFT^RNAi mutant cell lines (B-E) or of PF20^RNAi cells (F) that were induced for 72 hours. The typical flask-shape of the flagellar pocket is altered and vesicles frequently accumulate in the lumen (D,E). A, anterior side of the flagellar pocket; P, posterior side; K, kinetoplast; BB, basal body; TR, transition region. Black arrows indicate the tight contact between the top of the flagellar pocket and the flagellum, the white arrow indicates a vesicle in the flagellar compartment and the arrowheads indicate excessive IFT material typical of retrograde transport defects. (G) Quantification of sections with the indicated phenotypes in wild-type (WT) and various IFT^RNAi cell lines. WT, n=73; DHC1b^RNAi, n=51; IFT140^RNAi, n=36; IFT88^RNAi, n=28; IFT172^RNAi, n=31.