Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

The best I've been able to find is that there's a feedback mechanism, but what is this feedback, and how does the mechanism work? If it's just that the concentration of thymidine is too high, why won't excess quantities of other nucleotides do the same thing? (Or do they, and I don't know about it?)

share|improve this question
up vote 1 down vote accepted

Excess thymidine in a mitotic cell generates negative feedback on the production of deoxycytidine triphosphate from cytidine-5'-phosphate. Excess quantities of deoxyadenosine and deoxyguanosine also block progression through S-phase. However, as a reagent for the control of replication timing, thymidine has been found to work best as its blocking activity can be applied and reversed more consistently.

Xeros N. (1962) Deoxyriboside Control and Synchronization of Mitosis. Nature 194: 682-683.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.