BUdR

Date:
1970
Reference:
PP/CRI/H/4/18
Catalogue details

Licence: In copyright

Credit: BUdR. Source: Wellcome Collection.

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    protein is being produced. In addition, for any particular cell the exact details of the positions of the BUdR (if substitution is less than 100%) will determine which genes in that cell are most affected. As the same genes in other cells may not have BUdR in critical positions, the average level of a given protein, for all the cells in the culture, might be only reduced slightly, whereas in a certain percentage of cells that particular protein might be appreciably dud. In short, every cell in the culture might repro duce slowly because each had some enzymes (but not all) which were partly defective. Thus it is important to do RUdR experiments at as low a level of -4 BUdR as is possible for the phenomenon concerned. I suspect 1. 6 x 10 is too high for most purposes. If 1. 6 x 10 ^ is enough to prevent both fusion and the produc tion of muscle protein, then perhaps one should aim at, say, 2 x 10 ^M, and a second set of experiments (to get a second dose, which for some theories is important) at say 6 x 10 ^M. 2. In any critical quantitative experiment it really is important to measure the amount of BUdR incorporated in the DNA in that experiment . Admittedly this will probably be an average figure, and therefore not very accurate, but an approximate value is better than no value at all. 3. Sydney's assumption i s that (at doses of BUdR which are not too high - see above) the production of dud protein is unimportant. If this is true then it follows that complementation at the protein level can be ignored. Sydney phrased this by saying the interference of BUdR with base-pairing i s irrelevant