FIG. 5.

Synthesis of pyrG, RNA, and protein during CTP limitation. (A) Rate of synthesis from a pyrG::lacLM chromosomal fusion mutant (CJ217) grown in GSA defined medium with cytidine (○) or with cytidine and uridine (•). (B and C) Synthesis of RNA (squares) and protein (triangles), respectively, either during growth with cytidine (open symbols) or during growth with cytidine and uridine (CTP limitation) (closed symbols). Uridine (500 μg/ml) was added at an OD₄₃₆ of 0.2. The amount of incorporated labeled adenine or leucine in a 10-min pulse-labeling is set to 100 for the first determination for cells grown only with cytidine in the medium and is plotted against the OD value after 5 min of labeling.