The Caenorhabditis elegans centrosomal protein SPD-2 is required for both pericentriolar material recruitment and centriole duplication.
BACKGROUND
The centrosome is composed of a centriole pair and pericentriolar material (PCM). By marking the site of PCM assembly, the centrioles define the number of centrosomes present in the cell. The PCM, in turn, is responsible for the microtubule (MT) nucleation activity of centrosomes. Therefore, in order to assemble a functional bipolar mitotic spindle, a cell needs to control both centriole duplication and PCM recruitment. To date, however, the molecular mechanisms that govern these two processes still remain poorly understood.


RESULTS
Here we show that SPD-2 is a novel component of the C. elegans centrosome. SPD-2 localizes to the centriole throughout the cell cycle and accumulates on the PCM during mitosis. We show that SPD-2 requires SPD-5 for its accumulation on the PCM and that in the absence of SPD-2, centrosome assembly fails. We further show that centriole duplication is also defective in spd-2(RNAi) embryos, but not in spd-5(RNAi) embryos, where PCM recruitment is efficiently blocked.


CONCLUSIONS
Taken together, our results suggest that SPD-2 may link PCM recruitment and centriole duplication in C. elegans. SPD-2 shares homology with a human centrosome protein, suggesting that this key component of the C. elegans centrosome is evolutionarily conserved.
Pelletier
Laurence
L
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany. pelletie@mpi-cbg.de
Ozlü
Nurhan
N
Hannak
Eva
E
Cowan
Carrie
C
Habermann
Bianca
B
Ruer
Martine
M
Müller-Reichert
Thomas
T
Hyman
Anthony A
AA
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002502:Centrioles / Q000502:physiology*; D018385:Centrosome / Q000502:physiology*; D019295:Computational Biology; D017931:DNA Primers; D004625:Embryo, Nonmammalian / Q000648:ultrastructure; D049452:Green Fluorescent Proteins; D007150:Immunohistochemistry; D008164:Luminescent Proteins; D008780:Methyltransferases; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D017931:DNA Primers; D008164:Luminescent Proteins; C486131:SPD-2 protein, C elegans; D049452:Green Fluorescent Proteins; C490112:pcm-1 protein, C elegans; D008780:Methyltransferases