Fig. 3. RNA interference of TbARL1 expression. (A) Growth of the T. brucei bloodstream form (BSF) transfected line Bp2T7/ARL1 in the absence (open squares) and presence (filled squares) of tetracycline, monitored over a 5 day time course. (B) Northern blots of RNA (10 µg) from procyclic strain 29-13 (PCF), bloodstream parental line 90-13 (BSF) and transfected line Bp2T7/ARL1 grown in the absence (No Tet) and presence (+Tet) of tetracycline for 24 hours. The blot was hybridised with an ARL1-specific probe, and with ß-tubulin to monitor equal sample loading. (C) Nuclei and kinetoplasts were counted in parasitic line Bp2T7/ARL1 in the absence (light shading) and presence (dark shading) of tetracycline, over a 48 hour time course. Any configurations other than K1N1, K2N1 and K2N2 were classified as abnormal. 250 parasites were counted per experimental group. (D) Representative images of Bp2T7/ARL1 parasites with abnormal nucleus/kinetoplast configurations after induction with tetracycline for 36 hours. DAPI-stained cells are shown (a,b) with corresponding phase contrast images (a',b'). (E) Growth of the procyclic transfected line Pp2T7/ARL1 in the absence (open symbols) and presence (filled symbols) of tetracycline over a 5 day time course. Bar, 10 µm.