Cell division is a process essential for life. There are two types of cell division in mammalian cells: meiosis and mitosis. Meiosis is a type of cell division specific to germ cells, allowing the formation of fertilisation-competent sperm and eggs. Mitosis allows a single-celled fertilised egg to develop into a mature organism, and also allows hair, skin, blood cells, and internal organs to be renewed. During each cell division, the cell must divide two copies of the genome equally between two daughter cells. Errors that occur during this process in the oocyte can lead to spontaneous abortion and birth defects, whilst errors occurring in somatic cells lead to genetic instability, and are a hallmark of cancer. It is therefore essential to understand how this fundamental process occurs.
The phase of cell division during which the chromosomes are physically separated is called anaphase. Although anaphase has fascinated generations of scientists for more than a century, the mechanisms that underlie the poleward movement of the chromosomes in mammals are still unclear. Several studies have suggested candidate proteins that may power their movement, however there were no conclusive results due to the technically challenging nature of this research. The main reason for this challenge is that one must efficiently inactivate the candidate protein(s) only at the onset of anaphase so as to avoid disrupting the previous phases of cell division, which could confound the results.
Technologies to rapidly inactivate proteins of interest have recently become available. Here, we proposed to use these techniques to systematically dissect the mechanism(s) underlying poleward chromosome movement during anaphase in both mammalian germ cells (oocytes, meiosis) and non-transformed mammalian somatic cells (mitosis) in order to understand how chromosomes are separated during anaphase.
