RNAi of BILBO1 Disrupts Cytokinesis

(A) WT and BILBO1 RNAi PF cells were scored for kinetoplast/nuclei by DAPI labelling at 0, 24 h, and 36 h postinduction (+ TET). After 36 h of induction, a large number of 2K2N cell types are produced, and the proportion of the 2K1N cell type diminishes significantly. Induced cells arrest in the 2K2N configuration. The “Round” category represents round PF cells in which neither the nucleus nor the kinetoplasts could be individually distinguished. The “Other” categories represent cells in which 2N or 2K could not be assessed.

(B) The distribution of 2K2N cell types in WT and BILBO1 RNAi-induced cells (36 h). Cell morphology was scored by phase contrast microscopy and DAPI labelling as well as for the number of cells with flagella that had lost their flagellum-to-cell body attachment. The “Other” 2K2N category represents PF cells in which the position of the flagellum could not be assessed. Five distinctive 2K2N phenotypes were observed in induced PF cells: (1) 2K2N cells that appeared normal in kinetoplast and nuclear positioning (KNKN [8.96% SE ± 0.82%]); (2) KNKN cells with a loss of new flagellum-to-cell body attachment (20.56% SE ± 1.76%); (3) KKNN cells with a loss of new flagellum-to-cell body attachment (9.63% SE ± 0.63%); (4) elongated KNKN cells (18.33% SE ± 3.01%); and (5) elongated KKNN cells (41.73% SE ± 2.3%).