Figure 1. Native architecture of the core cartwheel in vivo.

(a–c) Images from cryo-tomogram of purified Chlamydomonas centriole (probasal body) after nine-fold symmetrization (left, three regions from top to bottom of centriole), with corresponding insets of boxed regions (right). (d) Schematic of centriole in b, with corresponding inset. (e) Native architecture of core cartwheel after symmetrization, highlighting the hub, as well as D1 and D2 densities. (f) Measurements of centriole features (see e): hub diameter (22.4±1.3 nm, n=10), distances from the hub margin to D1 (37±1 nm, n=13) and D2 (45.6±0.8 nm, n=13). Data extracted from five tomograms. Scale bars correspond to 50 nm.