Figure S5. Comparison of inner scaffolds and Arm A–Arm B scaffolds in centrioles from different species.

(A, B, C) (Left) Cross-sectional slices from raw tomograms through the region at the beginning of the transition from complete to incomplete triplets in the (A) WT mouse photoreceptor (this work), (B) CHO cell (Greenan et al, 2018), and (C) Tetrahymena (Le Guennec et al, 2020). The regions outlined with dashed-line boxes are shown to the right rotated 90° to the right into the plane of the page, and show Arm A extending from the A/B junction. The corresponding intensity profiles (far right) display similar periodicity among the species (∼8.4 and 8.5 nm). (D, E) Different views (tilted cutaway views from the lumen of the MT bundle, and cross-sectional views of the models from mouse rod photoreceptors and P. tetraurelia (E)) are shown, with the incomplete microtubule triplet in blue (mouse rod, (D)) or violet (P. tetraurelia, (E)) and Arm A–Arm B in gold. (D) Stem density connecting the two is colored yellow in the P. tetraurelia map, but this feature is much weaker and not visualized at this contour level in the mouse rod (D). (D, E) Inside views from the centriole interior show the attached inner scaffold with spacing at ∼8.4 nm for mouse photoreceptor (D) and ∼8.5 nm for P. tetraurelia (E).