Meiosis, the specialized form of cell division responsible for generating the gametes necessary for sexual reproduction, is still only a partially understood process – we have a good understanding of the major steps, by still lack understanding of the specifics of how it actually works. For example, how are the different processes coordinated?
Blitzblau and Hochwagen are two researchers who wanted to understand how the cell insures that the chromosomes have finished replicating prior to being reshuffled – a very important process, since disruption of it can spur a range of birth defects, including Down syndrome.
To do so, they chose to work with budding yeast, a model organism due to its chromosome replication and regulation being similar to that of humans. They began inhibiting the activity of individual proteins through a series of manipulations, until they found two enzymes that seemed critical for meiosis: Mec1 (which they found was similar to ATR, an enzyme known to play a role in DNA damage checkpoint activation) and DDK. Mec1 “senses” when the chromosomes are being replicated and transmits a molecular “wait” signal to DDK. When replication is done, the signal is terminated, and DDK becomes activated.
Press release: http://bit.ly/1bwjod6