nine-fold symmetry

The mechanism of the nine-fold symmetry formation that is unique to centrioles, basal bodies and cilia: Centriole, basal body and the cilium skeleton, termed the axoneme, share a unique nine-fold symmetry that accentuates their common origin. To study how this symmetry is formed we have identified three genes that are required specifically for centriole, basal body and cilium formation in Drosophila. One of these genes has an ortholog in humans that plays a critical role in a brain developmental disease and our results indicate that the protein encoded by this gene is involved in the early steps of centriole formation.