Discovery
sheds light on the way cells pass information between generations.
Biologists at Cornell University in Ithaca, N.Y., have shown
how tiny molecular motors carrying target proteins help
orient the spindle-like apparatus that transfers genetic
material from the nucleus of a mother cell to the daughter.
Immunofluorescence microscope photograph of yeast cells
with mutant molecular motors, left, and normal motor, right.
The
research explains an essential mechanism in the birth
of a new cell, and how failures of molecular motors can
have dire consequences for new cell formation.
Molecular
motors are tiny specialized structures that are fueled
by cellular energy in the form of adenosine triphosphate.
They perform a variety of tasks within cells. Mitosis
is the process by which a mother cell's nucleus divides
to provide a duplicate set of genetic instructions to
the developing daughter cell, in the form of chromosomes.
This transfer of genetic material is absolutely essential
for all organisms because without genetic instructions,
new cells cannot develop.
Even minor problems in mitosis can cause serious defects,
such as the development of cancerous cells. The new model
for mitotic mechanics, reported in the journal Nature,was
worked out in budding yeast cells, shown here. But the
study is expected to prompt further research into whether
similar processes occur in the formation of cells of all
higher organisms, including humans.
“The process of properly orienting the spindle with
the axis of cell division has to be incredibly accurate,
otherwise cells run the risk of not transferring their
genetic material into newly formed daughter cells,”
says Anthony Bretscher, professor of molecular biology
and genetics at Cornell and one of four authors of the
report. “This is the first time anyone could draw
a molecular mechanism for spindle orientation in yeast.
The big question is does this also happen in human cells?”
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