Time dependency of a critical effect of EGTA on DNA synthesis in cultures of Swiss 3T3 cells.
In a temporal analysis of the mitogenic response to serum, a critical period has been demonstrated just prior to the onset of replicative DNA synthesis during which transient calcium depletion blocks the subsequent entry of the cells into the S phase of the mitotic cycle. Transient washington of monolayer cultures of 3T3 cells with 2.5 mM EGTA between 6 and 8 h after serum-stimulated initiation of DNA synthesis was found to reduce cell-associated calcium levels and to inhibit thymidine incorporation, whereas similar treatment before (1-5 h) and after (8-9 h) had no detectable effect on either of these parameters when estimated after 21 h incubation. The effects during the chelation-sensitive period were reversed by the subsequent addition of fresh serum.
D000818:Animals; D001769:Blood; D002118:Calcium / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis*; D004533:Egtazic Acid / Q000494:pharmacology; D051379:Mice; D013997:Time Factors
D004533:Egtazic Acid; D004247:DNA; D002118:Calcium