Scientists have made the stunning discovery that chromosomes play an important role in animal cell division.
A research team observed the process in which chromosomes aid in cell division during cytokinesis, when the cell splits to form two daughter cells, the University of Montreal reported. Cell division is an essential part of life, but the process is not fully understood. Until now it was also not known that chromosomes were involved in cytokinesis.
Division is a complex and robust process that is generally performed flawlessly, but when an error occurs in DNA separation or during cytokinesis, it can be a source for triggering cancer, for example," said Gilles Hickson, an assistant professor at the University of Montreal's Department of Pathology and Cell Biology and researcher at the CHU Sainte-Justine Research Center.
It is already known that microscopic cable-like structures, called microtubules, work to pull chromosomes to opposite ends of the poles during the process of cell division.
"At this time, microtubules physically separate the chromosomes via their central kinetochores while other microtubules signal to the cortex of the cell where its equator is, i.e., where division will take place," Hickson said.
Before these groundbreaking observations, it had been thought that chromosomes only played a passive role in cell division, and did not influence cytokinesis as they were pulled by the microtubules. The findings suggest chromosomes actually emit signals that signals the cell cortex to reinforce microtubule action. An analysis of the genomes of flies revealed one of the key signals in this process is a phosphatase known as Sds22-PP1.
"Such evolutionary conservation from flies to humans is expected for processes as fundamental as cell division," Hickson said. "When chromosomes are segregated, they approach the membrane at the poles of the cell, and thanks to this enzyme's actions, this contributes to the softening of the polar membrane, facilitating the elongation of the cell and the ensuing division that occurs at the equator."
The new findings are being thought of as a breakthrough in our knowledge of the cell division process.
"We have been watching cells divide for more than 100 years, but we continue to seek to understand the molecular mechanisms involved. This is important because cell division is so central to life, and to certain diseases," Hickson said.
The findings were reported in a recent edition of the journal Nature.
