(Georgia Institute of Technology, 2010-09-08)
The growth and reproduction of all living organisms are dependent on the cell cycle, the process which leads to cell division. Uncontrolled division of cells is important for disease particularly cancer. Two events, S-phase and mitosis, are common to all cell cycles and are necessary for the two newly divided cells to receive a full complement of genes. In fission yeast the onset of S-phase and mitosis are controlled by a single cyclin dependent kinase with different levels of CDK activity bringing about progression through the cell cycle in an ordered fashion. Activation of CDK activity is determined by growth rate and cell size, with cell size determined by a gradient mechanism with controlling molecules diffusing from the periphery of the cell to be sensed in the middle of the cell.