Centriole assembly in Caenorhabditis elegans.
Centrioles are necessary for flagella and cilia formation, cytokinesis, cell-cycle control and centrosome organization/spindle assembly. They duplicate once per cell cycle, but the mechanisms underlying their duplication remain unclear. Here we show using electron tomography of staged C. elegans one-cell embryos that daughter centriole assembly begins with the formation and elongation of a central tube followed by the peripheral assembly of nine singlet microtubules. Tube formation and elongation is dependent on the SAS-5 and SAS-6 proteins, whereas the assembly of singlet microtubules onto the central tube depends on SAS-4. We further show that centriole assembly is triggered by an upstream signal mediated by SPD-2 and ZYG-1. These results define a structural pathway for the assembly of a daughter centriole and should have general relevance for future studies on centriole assembly in other organisms.
Pelletier
Laurence
L
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany. pelletie@mpi-cbg.de
O'Toole
Eileen
E
Schwager
Anne
A
Hyman
Anthony A
AA
Müller-Reichert
Thomas
T
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D029742:Caenorhabditis elegans Proteins / Q000502:physiology; D002502:Centrioles / Q000502:physiology* / Q000648:ultrastructure; D005260:Female; D008297:Male; D011494:Protein Kinases / Q000502:physiology; D034622:RNA Interference
D029742:Caenorhabditis elegans Proteins; C486131:SPD-2 protein, C elegans; D011494:Protein Kinases; C429649:zyg-1 protein, C elegans