Abstract

A large number of molecular, physiological, and biochemical events accompany the mitogen‐induced transition from a quiescent, nonproliferating state to a cycling state. However, it is difficult to distinguish causal steps in the commitment to cell division from correlative events. To approach this problem we have isolated mitogen‐specific nonproliferative variants of 3T3 cells, namely cell lines that are unable to mount a mitogenic response to specific mitogens.