Problem,:

Is it possible to select from colonies only cells which are at a certain stage in the cell cycle? E.g. if I was trying to analyse expression of a number of genes during different stages of the cell cycle.

I could imagine that if this is possible, the selection mechanism might target cyclins, or use an artificial gene cassette controlled by them.
So for example, a method may attach some gene to a certain cyclin which protects against a substance that otherwise destroys the cell. We could then use that substance to destroy all cells which were not in the cell cycle stage that we want to look at, wash away their nucleic acids, and then extract the mRNA from remaining cells to analyse expression levels at this particular stage in the cell cycle. If we repeat that for the different stages, we should be able to get a nice picture of what is expressed when.

Does any method like this exist or is commonly used? Justify your answer.