A kinetic model for microtubule polymerization during oral regeneration in Stentor coeruleus.

The regeneration of oral cilia in the protozoan cell, Stentor coeruleus, has been investigated in the presence of agents which do not favor the polymerization of microtubules. These agents, low temperature and the tubulin binding drugs, podophyllotoxin and beta-peltatin, slow the rate of regeneration. A kinetic model is proposed to test the hypothesis that microtubule polymerization is the rate limiting step in oral regeneration. The results suggest that the tubulin concentration of normal regenerating cells is slightly in excess of an amount which would kinetically limit the regeneration rate.