2 research outputs found
Conformation of cytoskeletal elements during the division of infected Lupinus albus L. nodule cells
11 pages and figuresLupin nodule cells maintain their ability to divide for
several cycles after being infected by endosymbiotic
rhizobia. The conformation of the cytoskeletal elements
of nodule cells was studied by fluorescence labelling,
immunocytochemistry, and laser confocal and transmission
electron microscopy. The dividing infected
cells showed the normal microtubule and actin patterns
of dividing plant cells. The clustered symbiosomes
were tethered to the spindle-pole regions and moved
to the cell poles during spindle elongation. In metaphase,
anaphase, and early telophase, the symbiosomes
were found at opposite cell poles where they
did not interfere with the spindle filaments or phragmoplast.
This symbiosome positioning was comparable
with that of the organelles (which ensures organelle
inheritance during plant cell mitosis). Tubulin microtubules
and actin microfilaments appeared to be in
contact with the symbiosomes. The possible presence
of actin molecular motor myosin in nodules was
analysed using a monoclonal antibody against the
myosin light chain. The antigen was detected in protein
extracts of nodule and root cytosol as bands of
approximately 20 kDa (the size expected). In the nodules,
an additional polypeptide of 65 kDa was found.
Immunogold techniques revealed the antigen to be
localized over thin microfilaments linked to the cell
wall, as well as over the thicker microfilament bundles
and surrounding the symbiosomes. The pattern of
cytoskeleton rearrangement in dividing infected cells,
along with the presence of myosin antigen, suggests
that the positioning of symbiosomes in lupin nodule
cells might depend on the same mechanisms used to
partition genuine plant cell organelles during mitosisPeer reviewe