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Cell division drama unfolds under the microscope
Separation of chromosomes during cell division in the Drosophila embryo. The DNA of the chromosomes is shown in red. During division, the chromosomes are attached to a cage-like structure at their midpoint, the 'centromere', which is shown here in green
It's the most dramatic step in cell division and the point of no return in this perfectly orchestrated series of events - the moment when the two sets of chromosomes are pulled apart as a single cell prepares to become two.
Now a collaboration between two groups of researchers in the Biochemistry Department has revealed details of how animal cells control entry into this part of the cell division cycle, known as anaphase.
The work provides a handle on the molecular events underlying cell division which are crucial to our understanding of how cancer develops.
Professors Kim Nasmyth and Ilan Davis and members of their groups have just published their findings in Nature Cell Biology1.
Researchers have known for some time that the two sets of newly replicated chromosomes are held together until they are ready to separate by a protein known as cohesin. Studies by Professor Nasmyth and others have demonstrated that in yeast, destroying cohesin is enough to trigger separation of the chromosomes.
Nuclei dividing in an early stage Drosophila embryo. Each nucleus contains two sets of chromosomes which must be aligned neatly before they divide to opposite poles, forming two new daughter nuclei. DNA is shown in red and centromeres in green.
Cohesin is also found in animal cells but researchers have puzzled over whether these cells might rely on a more complicated set of signals to trigger anaphase. The meagre amount of cohesin found on the chromosomes hints that this may be the case.