Fig. 2: Cryo-electron tomography (Cryo-ET) of MT singlet-to-doublet transition.

A A 0.9 nm thick tomographic slice exhibits the proximal part of the male gamete in the P. yoelii 17XNL parasite. The A-tubule (blue) and B-tubule (green) of MT doublet were indicated by arrows. A representative from two independent experiments. Scale bars = 50 nm. B 3D rendering of tomograms for the male gamete in (A). MT doublet’s A-tubule (blue) and B-tubule (green) are colored. A central pair of MT singlets (yellow) and the parasite plasma membrane (PM) was denoted. Scale bars = 50 nm. C Cross-section view (left) and 3D rendering (right) of MTs in axoneme (slice 1) and basal body (slice 2) from (B). A representative from two independent experiments. Scale bars = 50 nm. A-tubule (blue), B-tubule (green), and parasite plasma membrane (white) were indicated by arrowheads. D–F A 0.9 nm thick tomographic slices and 3D rendering of tomogram showing the proximal part of another male gamete. A representative from two independent experiments. G Vertical-section and cross-section views of a Cryo-ET tomogram showing the MT singlet-to-doublet transition in the BB of the male gamete. In the left panels, two slices from the same tomogram were shown, with each slice being 2 nm thick. Six slices (pink dash lines positioned in the cross sections) were shown in the right panels. A representative from two independent experiments. Scale bars = 100 nm. H Quantification of the distance between the proximal end of A-tubule and B-tubule in the MT doublet. Left panel is a schematic showing the distance measured. Mean ± SD for the MT doublets (n = 98) measured from two independent experiments, two-tailed t-test. I Vertical-section view showing the proximal end of the A-tubule (blue arrowhead) and B-tubule (green arrowhead) in the MT doublets from two different Cryo-ET tomograms. A representative from two independent experiments. Scale bars = 50 nm. J A schematic of the MT singlet-to-doublet transition in the BB for axonemal MT doublet assembly in the P. yoelii. Source data are provided as a Source Data file.