Higher plant cells: gamma-tubulin and microtubule nucleation in the absence of centrosomes.
The assembly of the higher plant cytoskeleton poses several fundamental questions. Since different microtubule arrays are successively assembled during the cell cycle in the absence of centrosomes, we can ask how these arrays are assembled and spatially organized. Two hypotheses are under debate. Either multiple nucleation sites are responsible for the assembly and organization of microtubule arrays or microtubule nucleation takes place at one site, the nuclear surface. In the latter case, microtubule nucleation and organization would be two distinct but coregulated processes. During recent years, novel approaches have provided entirely new insights to understand the assembly and dynamics of the plant cytoskeleton. In the present review, we summarize advances made in microscopy and in molecular biology which lead to novel hypotheses and open up new fields of investigation. From the results obtained, it is clear that the higher plant cell is a powerful model system to investigate cytoskeletal organization in acentrosomal eukaryotic cells.
Canaday
J
J
Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, Université Louis Pasteur, Strasbourg, France.
Stoppin-Mellet
V
V
Mutterer
J
J
Lambert
A M
AM
Schmit
A C
AC
D000199:Actins / Q000502:physiology; D015153:Blotting, Western; D002453:Cell Cycle / Q000502:physiology*; D003599:Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D018613:Microscopy, Confocal; D008869:Microtubule-Associated Proteins / Q000032:analysis; D008870:Microtubules / Q000737:chemistry / Q000502:physiology*; D009154:Mutation; D018521:Plant Physiological Phenomena; D014404:Tubulin / Q000032:analysis / Q000235:genetics / Q000502:physiology
D000199:Actins; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D014404:Tubulin; D049452:Green Fluorescent Proteins