pH shock–induced flagellar regeneration and NaPPi-induced flagellar shortening in wild-type and dhc1b-3 cells at 21 and 34°C. (A) Wild-type and dhc1b-3 cells were incubated at 21 or 34°C (6 h, 12 h), deflagellated with pH shock, allowed to recover at 21 or 34°C, then scored after 2 h recovery for the percentage of deflagellated cells (regeneration failure). Although the extent of dhc1b-3 flagellar regeneration at 21°C was similar to wild-type, dhc1b-3 cells showed strong flagellar assembly defects at 34°C. Ncells = 2,335 from two experiments. (B) Cells were grown in M media, incubated for 12 h at 21 or 34°C, and then treated with 20 mM NaPPi. The flagella of wild-type and dhc1b-3 cells (mt+ and mt− strains) shortened with similar rates (∼3 µm/h) at both 21 and 34°C. Thus, NaPPi-induced flagellar shortening may be independent of retrograde IFT. The starting flagellar lengths of both mutant and wild-type strains were slightly shorter than normal, likely due to unknown variations in the culture conditions. Error bars indicate standard deviation. Nflagella = 540 from a single experiment.
