Figure 3.

Central pair defects originate at the basal plate. (A-C) Serial thin section electron micrographs through the basal plate region of non-induced (A) and TbHydin RNAi-induced (B and C) cells. In non-induced cells, the two central pair tubules are nucleated simultaneously (A, arrows), however only a single central pair tubule is present in the TbHydin RNA-induced cell (B, arrow). (C) serial thin sectioning of TbHydin RNA-induced cells from the basal plate through to where the flagellum exits the flagellar pocket demonstrates that the central pair mispositioning defect also originates at the basal plate. Central pair position is determined relative to the PFR (arrow). Note how this position is invariant throughout the series. Scale bars = 200 nm.