Regulation of mitosis onset and thymidine kinase activity during the cell cycle of Physarum polycephalum plasmodia: effect of fluorodeoxyuridine.

摘要: The effects of fluorodeoxyuridine were investigated during three events the cell cycle: S-phase, mitosis, and cyclic synthesis thymidine kinase in synchronous plasmodium myxomycete Physarum. DNA was inhibited, there limited action on other macromolecular syntheses. When slowed down, onset following increase occurred at approximately same time as control, but mitosis blocked a very early prophase stage metaphase never observed. These suppressed when prevented by addition to medium. In agreement with aphidicolin hydroxyurea, these observations show that: 1) perturbation S-phase does not prevent nuclei from entering stage, it them proceeding through metaphase; 2) blockage perturb normal timing triggering synthesis; 3) signal that triggers arrest is postmitotic require extensive synthesis. contrast hydroxyurea aphidicolin, presence Thus, unambiguously dissociated events. Because remains under control temperature shifts 22 32 degrees C, simple model cycle involving two regulatory pathways could account for synthesis, metaphase.