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Videos of Actin Dynamics
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Our major interest is in actin dynamics
in dendritic spines, shown in the top set of movies. Recordings
of actin dynamics in growth cones of developing neurons and in
non-neuronal cells are shown further down this page. Unless otherwise
stated this data is taken from Fisher et al. 1998 Neuron 20:847-854.
DYNAMICS IN DENDRITIC SPINES
DYNAMICS IN GROWTH CONES
||(3.2 MB). Growth cone of a
hippocampal neuron after 48 hours in dispersed cell culture.
Actin is concentrated in the palm of the growth cone and forms
motile filopodia and lammelipodia. Note the far lower actin levels
in the shaft of the growing axon behind the growth cone.
||(4 MB). Another hippocampal
neuron growth cone with well-marked filopodial activity. (Unpublished
DYNAMICS IN FIBROBLASTIC CELLS
|| (861 KB). This
sequence shows the edge of a rat embryo fibroblast that was transfected
with actin tagged with green fluorescent protein (GFPactin).
The tagged actin gets incorporated into actin filaments so that
they are visible inside the living cell when it is examined with
a fluorescence m icroscope. Notice that actin can support two
distinct kinds of structures - the highly motile ones at the
edge of the cell, where actin polymers are rapidly forming and
dissociating again, and relativelt stable ones like the thick
bundles of filaments (stress fibres) deeper in the cell. Unpublished
||(2.2 MB). A rat embryo fibroblast
migrating toward a "wound" (an area of the culture
close by where the cells were scrapted off the cover slip). The
area of membrane ruffling at the leading edge of the cell is
rich in dynamic actin while the stress fibres in the body of
the cell change configuration much less quickly demonstrating
the "semi-conservative" way that actin mediates between
structural stability and plasticity.