Abstract 9600536 Tyson The cell division cycle is the periodic repetition of a sequence of events, including DNA synthesis, mitosis and cytokinesis, that transform a single cell into two daughter cells. Control of the sequence and timing of these events is complex. The major events are triggered by cyclin-dependent kinases, a family of enzymes whose activity depends on binding to the cyclin proteins, phosphorylation and binding to inhibitory proteins. So far characterization of this regulatory system has been reductionistic; breaking the nnetwork into parts and examining how they interact. This project will develop mathematical methods by which the parts can be put back together into a model of an intact, functional regulatory system. By comparing the behavior of the model to experimental observations, the credibility of the model can be judged. The goal is to develop realistic models of cell cycle control in frog embryos, yeast cells and mammalian cells. The experimental tools to dissect this control system are well developed, but the theoretical tools necessary to put the pieces together are still largely untested and underappreciated by cell biologists. This projects aims at developing appropriate mathematical tools, applying them to current data, and communicating the power of modeling the to the experimental community. ***
