FIG 1 .
RNAi knockdown of TbCet1 arrests growth of T. brucei. (A) Procyclic T. brucei 29.13-TbCet1RNAi transfectants were inoculated into medium containing 1.0 µg/ml tetracycline (+Tet) to induce TbCet1 dsRNA production and into a parallel control culture lacking tetracycline (−Tet). Cell density was monitored by microscopy and maintained between 1 × 106 and 1 × 107 cells/ml by dilution into fresh medium. The growth curves display on the y axis the log of the direct cell count multiplied by the dilution factor. Induction of RNAi against TbCet1 arrested T. brucei growth after 5 days. (B) Western blotting verifies knockdown of TbCet1 protein by RNAi induction. An anti-TbCet1 immunoblot assay of total protein from cells harvested from a +Tet culture is shown. The positions and sizes (kilodaltons) of marker polypeptides are indicated on the left. The immunoreactive TbCet1 polypeptide, denoted by the arrowhead at left, is depleted after RNAi induction. A nonspecific cross-reacting 50-Da polypeptide, indicated by the asterisk at right, is unchanged.