Continued initiation of DNA synthesis in arginine-deprived Chinese hamster ovary cells.
When exponentially growing CHO cells were deprived of arginine (Arg), cell multiplication ceased after 12 h, but initiation of DNA synthesis continued: after 48 h of starvation with continuous [3H]thymidine exposure, 85% of the population had incorporated label, as detected autoradiographically. Consideration of the distribution of exponential cells in the various cell cycle phases leads to a calculation that most cells in G1 at the time that Arg was removed, as well as those in S, engaged in some DNA synthesis during starvation. In contrast, isoleucine (Ile)-starved cells did not initiate DNA synthesis, as has been reported by others. Experiments with cells synchronized by mitotic selection confirmed this difference in Arg- and Ile- deprived behavior, but also showed that cells which underwent the mitosis leads to G1 transition during Arg starvation remained arrested in G1 (G0?). The results suggest that Arg-deprived cells continue to maintain some proliferative function(s) while Ile-deprived cells do not.
D001120:Arginine / Q000378:metabolism*; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival; D004247:DNA / Q000096:biosynthesis*; D007532:Isoleucine / Q000378:metabolism
D007532:Isoleucine; D004247:DNA; D001120:Arginine