Epsilon-tubulin is required for centriole duplication and microtubule organization.
Centrosomes nucleate microtubules and serve as poles of the mitotic spindle. Centrioles are a core component of centrosomes and duplicate once per cell cycle. We previously identified epsilon-tubulin as a new member of the tubulin superfamily that localizes asymmetrically to the two centrosomes after duplication. We show that recruitment of epsilon-tubulin to the new centrosome can only occur after exit from S phase and that epsilon-tubulin is associated with the sub-distal appendages of mature centrioles. Xenopus laevis epsilon-tubulin was cloned and shown to be similar to human epsilon-tubulin in both sequence and localization. Depletion of epsilon-tubulin from Xenopus egg extracts blocks centriole duplication in S phase and formation of organized centrosome-independent microtubule asters in M phase. We conclude that epsilon-tubulin is a component of the sub-distal appendages of the centriole, explaining its asymmetric localization to old and new centrosomes, and that epsilon-tubulin is required for centriole duplication and organization of the pericentriolar material.
Chang
Paul
P
Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
Giddings
Thomas H
TH
Winey
Mark
M
Stearns
Tim
T
D000818:Animals; D001483:Base Sequence; D002453:Cell Cycle / Q000502:physiology*; D002478:Cells, Cultured; D002502:Centrioles / Q000648:ultrastructure*; D003598:Cytoskeletal Proteins; D017931:DNA Primers; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism; D016350:Leucine Zippers; D008297:Male; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000648:ultrastructure*; D009687:Nuclear Proteins; D010063:Ovum / Q000166:cytology / Q000502:physiology; D020033:Protein Isoforms / Q000378:metabolism; D011898:Ranidae; D016196:S Phase; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology; D014404:Tubulin / Q000378:metabolism*
D003598:Cytoskeletal Proteins; D017931:DNA Primers; C512806:NIN protein, human; D009687:Nuclear Proteins; D020033:Protein Isoforms; D014404:Tubulin; D019204:GTP-Binding Proteins