The Wave Nature of Being: Ultradian Rhythms and Mind-Body Communication

We have produced extracts of frog eggs that can perform multiple cell cycles in vitro. Destruction of the endogenous messenger RNA arrests the extracts in interphase. The addition of exogenous cyclin mRNA is sufficient to produce multiple cell cycles. The newly synthesized cyclin protein accumulates during each interphase and is degraded at the end of each mitosis.

We show that cyclin plays a pivotal role in the control of mitosis. A proteolysis-resistant mutant of cyclin prevents the inactivation of maturation promoting factor and the exit from mitosis both in vivo and in vitro. We have used a fractionated extract to study the activation of MPF by added cyclin protein.