UK researchers find ‘safety catch’ in cell division machinery


Researchers from the Institute of Cancer Research, London, the University of Cambridge and University College Dublin have found how cellular machinery helps to govern cell division.

The discovery represents a step forward in understanding of the fundamental process of life.

It also is expected to lead to new treatments that prevent cancer cells from dividing, or also kill them by forcing them to divide prematurely.

The study has revealed a ‘safety catch’ within cells that prevents them from dividing until DNA is properly allocated to the two daughter cells.

As part of the study funded by Cancer Research UK, Wellcome, Science Foundation Ireland and the European Union, the researchers examined the role of a molecule called BubR1 in mitosis.

During mitosis, a cell copies its chromosomes and pulls them apart into two separate cells.

BubR1 forms part of a molecular machine that stops the two sets of chromosomes from being pulled apart and prevents cells from dividing until they are ready.

The Institute of Cancer Research, London Cancer Biology head professor Jon Pines said: “Our study has found a ‘safety catch’ in the cell division machinery, which prevents cells from dividing before they have confirmed that their chromosomes have been successfully aligned in the cell.

“In the future it might be possible to disable this safety catch in cancer cells with drugs, which would force cells into dividing before they are ready, and potentially kill them by introducing major errors into the division process.”

"The team’s focus was on a small portion of BubR1 conserved across evolution in all kingdoms of life except bacteria and removing the normal molecule from cells."

The team’s focus was on a small portion of BubR1 conserved across evolution in all kingdoms of life except bacteria and removing the normal molecule from cells.

After replacing it with an altered form that was mis-shapen in the crucial area, they timed how long cells with mutant BubR1 could be held up during the mitosis process using time-lapse photography on high-powered microscopes.

It was found that cells with mutant BubR1 were unable to delay in mitosis as normal, meaning chromosomes were not divided uniformly between daughter cells.

The researchers concluded that the crucial part of BubR1 acts as a safety catch and prevents the progression of mitosis until the chromosomes are properly positioned for separation.


Image: BubR1 forms part of a molecular machine that prevents cells from dividing until they are ready. Photo: courtesy of Professor Chris Bakal.