Figure 6. Adjacent Drosophila melanogaster S2 doublets are connected via a novel A-A linker.

(a) The doublet average was fit back into a centriole, which showed no signs of ice-induced flattening, allowing the exact geometry of the S2 centriole to be determined. From this refit it was clear that connections between adjacent doublets were through A-tubule to A-tubule links, hereafter referred to as the A-A linker. (b) A zoomed in view of one doublet in context, showed that the hinge-like structure from one doublet extended and attached to the elaborated pinhead of the adjacent doublet (orange double arrowheads). The second density between adjacent doublets (pink double arrowheads) makes weak connections to both the A-A linker and the A-tubule, and likely represents the brush-like structures that were observed emanating from between doublets in the tomograms. Scale bars are 100 nm in (a), and 25 nm in (b).

Figure 6—figure supplement 1. The proximal CHO and Drosophila centrioles have the same geometry, but different linkages.

(a) The symmetry of the proximal CHO centriole (Paintrand et al., 1992), as shown in Figure 5a. (b) The experimentally determined symmetry of the Drosophila centriole, as shown in Figure 7a. (c) An overlay of the two symmetries shows that while the geometry is identical, the positions and structures of the microtubules linkages are completely different. Scale bar is 100 nm.