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Do Centrioles Generate a Polar Ejection Force?

Jonathan Wells (2005) Do centrioles generate a polar ejection force? Riv Biol 98:71-95. PMID: 15889341

Abstract: A microtubule-dependent polar ejection force that pushes chromosomes away from spindle poles during prometaphase is observed in animal cells but not in the cells of higher plants. Elongating microtubules and kinesin-like motor molecules have been proposed as possible causes, but neither accounts for all the data. In the hypothesis proposed here a polar ejection force is generated by centrioles, which are found in animal cells but not in the cells of higher plants. Centrioles consist of nine microtubule triplets arranged like the blades of a tiny turbine. Instead of viewing centrioles through the spectacles of molecular reductionism and neo-Darwinism, this hypothesis assumes that they are holistically designed to be turbines. Orthogonally oriented centriolar turbines could generate oscillations in spindle microtubules that resemble the motion produced by a laboratory vortexer. The result would be a microtubule-mediated ejection force tending to move chromosomes away from the spindle axis and the poles. A rise in intracellular calcium at the onset of anaphase could regulate the polar ejection force by shutting down the centriolar turbines, but defective regulation could result in an excessive force that contributes to the chromosomal instability characteristic of most cancer cells.

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Jonathan Wells

Senior Fellow, Center for Science and Culture
Jonathan Wells has received two Ph.D.s, one in Molecular and Cell Biology from the University of California at Berkeley, and one in Religious Studies from Yale University. A Senior Fellow at Discovery Institute's Center for Science and Culture, he has previously worked as a postdoctoral research biologist at the University of California at Berkeley and the supervisor of a medical laboratory in Fairfield, California. He also taught biology at California State University in Hayward and continues to lecture on the subject.