Evidence for tektins in centrioles and axonemal microtubules. Affinity purified, polyclonal antibodies were prepared against three tektins (tektins A, B, and C) isolated from sea urchin sperm axonemal microtubules. These antibodies (anti-tektins) were used to localize tektins in axonemes, basal bodies, and centrioles. By immunofluorescence microscopy it could be demonstrated that in sperm tails from Lytechinus pictus all three anti-tektins stain all nine axonemal doublet microtubules and A-tubule extensions along their entire length. In addition to staining doublet microtubules, anti-tektin C weakly labeled the central-pair microtubules in sperm tails from Patiria miniata. The anti-tektin staining revealed also a clear cross-reaction with basal bodies of sea urchin sperm and with centrioles of cells from hamsters, humans, and pigs. These data provide evidence of tektin or tektin-like proteins in basal bodies and centrioles and suggest that centriole microtubules are constructed according to the same principles as flagellar microtubules.