The control of septum formation in fission yeast

If cell division is to produce two daughter cells that are viable, faithful copies of the parent cell, the landmark events of the cell division cycle, S phase, mitosis, and cytokinesis, must be executed in the correct order and with high fidelity. Though considerable advances have been made toward understanding the mechanisms that control the onset of S phase and mitosis, regulation of the events that occur at the end of the cell cycle, such as the reorganization of the cytoskeleton and the initiation of cell separation or cytokinesis, are less well understood. The fission yeastSchizosaccharomyces pombe provides a simple eukaryotic model for the study of cytokinesis. S. pombe cells are rod shaped, grow mainly by elongation at their ends, and divide by binary fission after forming a centrally placed division septum. Study of S. pombe mutants has begun to shed light on how septum formation and cytokinesis are regulated both spatially and temporally, to achieve proper co-ordination with mitosis. Some of the genes defined by these mutants have been functionally conserved through eukaryotic evolution, suggesting that aspects of this control will be common to all eukaryotic cells.