Chemically Induced Mitotic Synchrony in Root Apical Meristems

This chapter focuses on chemically induced mitotic synchrony in root apical meristems. Synchronization of the mitotic cell cycle is achieved by selectively but reversibly blocking the process at a defined step for a period of time equal to or greater than the time required to complete one cycle. Individual cells arrive at the arrest point at different times during the treatment period, depending upon the stage of the cycle in which they happened to be when the blocking agent was administered. The agent is then removed, freeing cells to proceed through the cycle in synchrony. Samples are collected and analyzed at appropriate time points following removal of the blocking agent. These harvests will be enriched for cells passing through the stage of the cycle that occurs at that particular interval following the arrest point. Key control points of the eukaryotic cell cycle occur at the G1/S and G2/M transitions. The 5-AU procedure provides an unperturbed G2/M passage. However, 5-aminouracil (5-AU)-treated root tip meristems do not maintain synchrony long enough to pass through the G1/S transition in sufficient synchrony for biochemical analyses of this control point to be of value.