Figure EV3. Very long cartwheel in T. mirabilis .

1. Differential interference contrast micrograph of live T. mirabilis cell. The arrow points to the cell anterior, where the rostrum is located; arrowheads point to some of the flagella.
2. Transmission electron micrograph of T. mirabilis centriole embedded in resin—longitudinal view. The hub (arrowhead) is visible in the proximal cartwheel‐bearing region (green line), but not in the distal region (black line).
3. Transmission electron micrograph of T. mirabilis centriole embedded in resin in transverse view (left) and corresponding image circularized and symmetrized (right). Note small density present inside the hub corresponding to the fCID. Centrioles shrink during chemical fixation and subsequent preparation, thus appearing smaller than in (D).
4. Transverse slice through cryo‐electron tomogram of T. mirabilis centriole circularized and symmetrized. Note the fCID presence inside the hub.
5. Distribution of sub‐volumes of the 64% (black circle) and 36% (white circle) classes along four T. mirabilis centrioles, proximal is left; areas with neither black nor white circle could not be clearly assigned to either class. Note that the distribution of the two classes is not stereotyped along the centriole.