Fig. 1

Basal body ultrastructure. At the distal end of the basal body, distal appendages or transition fibers are blades that have ninefold symmetry and radiate outward from the triplet microtubules. Proximal to the distal appendages is the basal foot, an electron-dense and cone-shaped structure projecting from one side of the basal body. Some basal bodies have multiple basal feet. The proximal end of the basal body is attached to the striated rootlet and to filaments that connect the basal body to the proximal end of the daughter centriole. Motile cilia in multiciliated cells lack associated daughter centrioles. Image credits: serial-section electron micrographs of transition fibers, the basal foot, and proximal basal body were originally published in [44]. Electron micrograph illustrating the striated rootlet and the daughter centriole was originally published in [14]