Fig. 1

Flagellum assembly is an early event during T. brucei differentiation in the PV. a–e Immunofluorescence assay using anti-FTZC (magenta) and mAb25 (green) antibodies as markers for TZ and Axoneme, respectively. DAPI was used for DNA staining (blue). a, b Trypomastigote cell with an oval nucleus, possessing either a single transition zone (TZ) and axoneme (a) or a second TZ (arrowhead) located laterally to the other one (b). c, d Trypomastigote cells with an elongated nucleus possessing either a single TZ and axoneme (c) or with a second axoneme (arrow) being assembled from the second TZ (arrowhead). e Late transition form, the kinetoplast is laterally disposed and located at the anterior half of the nucleus whereas the TZ of the new flagellum (arrowhead) is more distant from the TZ of the mature flagellum and the axoneme is being extended. f Graph showing the duplication of the TZ and the axoneme in the trypomastigote population from the PV. A total of 200 parasites were analysed, the percentages were calculated for trypomastigotes and transition forms. Flies were dissected 14 days post-infection. Abbreviations: Axo, axoneme; TZ, transition zone. Note: Anterior and posterior regions of the cell are indicated on panel a. Scale-bar: 5 µm