Isolated Plant Nuclei Nucleate Microtubule Assembly: The Nuclear Surface in Higher Plants Has Centrosome-like Activity.

AUTOR(ES)

Stoppin, V

RESUMO

In most eukaryotic cells, microtubules (MTs) are assembled at identified nucleating sites, such as centrosomes or spindle pole bodies. Higher plant cells do not possess such centrosome-like structures. Thus, the fundamental issues of where and how the intracellular plant MTs are nucleated remain highly debatable. A large body of evidence indicates that plant MTs emerge from the nuclear periphery. In this study, we developed an in vitro assay in which isolated maize nuclei nucleate MT assembly at a tubulin concentration (14 [mu]M of neurotubulin) that is not efficient for spontaneous MT assembly. No MT-stabilizing agents, such as taxol or dimethyl sulfoxide, were used. Our model provides evidence that the nuclear surface functions as a MT-nucleating site in higher plant cells. A monoclonal antibody raised against a pericentriolar antigen immunostained the surface of isolated nuclei, and a 100-kD polypeptide in 4 M urea-treated nuclear extracts was detected.

Documentos Relacionados

• Nuclear localization signal binding proteins in higher plant nuclei.
• Nuclear import in permeabilized protoplasts from higher plants has unique features.
• Interference of GTP hydrolysis in the mechanism of microtubule assembly: an experimental study.
• Thermodynamic and structural analysis of microtubule assembly: the role of GTP hydrolysis.
• Chromatin assembly in isolated mammalian nuclei.