Microtubule nucleation in yeast and animal cells is initiated byγ-tubulin ring complexes (γ-TuRCs) associated with centrosomes or spindle pole bodies. Microtubule nucleation in plants is less well understood:the microtubule arrays differ significantly from those in animals and lack centrosome-like microtubule-organizing centres (MTOCs). Moreover,γ-tubulin is distributed along plant microtubules rather than at one end, which is perplexing given its role in nucleation in animals and yeast. Anne-Catherine Schmit and co-workers now provide evidence that plants do in fact use γ-TuRC-like structures to nucleate microtubules (seep. 2423). They have cloned and characterized rice and Arabidopsis orthologues of the γ-TuRC component SPC98, demonstrating that higher plants contain γ-TuRC components other than γ-tubulin. Significantly, SPC98 does not colocalize with γ-tubulin along the length of plant microtubules but does colocalize with it at the nuclear surface and cell cortex - locations for putative plant MTOCs. These findings suggest that γ-TuRCs containing SPC98 and...

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