THE PLANT CELL, Vol 2, Issue 2 129-138, Copyright © 1990 by American Society of Plant Biologists
Microinjected Fluorescent Phalloidin in Vivo Reveals the F-Actin Dynamics and Assembly in Higher Plant Mitotic Cells
A. C. Schmit and A. M. Lambert
Laboratoire de Biologie Cellulaire Vegetale, Universite Louis Pasteur, Centre National de la Recherche Scientifique, Unite Associee 1182, Institut de Botanique, 28, rue Goethe, F-67083 Strasbourg Cedex, France
Endosperm mitotic cells microinjected with fluorescent phalloidin enabled
us to follow the in vivo dynamics of the F-actin cytoskeleton. The
fluorescent probe immediately bound to plant microfilaments. First, we
investigated the active rearrangement of F-actin during chromosome
migration, which appeared to be slowed down in the presence of phalloidin.
These findings were compared with the actin patterns observed in mitotic
cells fixed at different stages. Our second aim was to determine the origin
of the actin filaments that appear at the equator during anaphase-telophase
transition. It is not clear whether this F-actin is newly assembled at the
end of mitosis and could control plant cytokinesis or whether it
corresponds to a passive redistribution of broken polymers in response to
microtubule dynamics. We microinjected the same cells twice, first in
metaphase with rhodamine-phalloidin and then in late anaphase with
fluorescein isothiocyanate-phalloidin. This technique enabled us to
visualize two F-actin populations that are not co-localized, suggesting
that actin is newly assembled during cell plate development. These in vivo
data shed new light on the role of actin in plant mitosis and cytokinesis.
