Yeast as a model system for understanding the control of DNA replication in eukaryotes

摘要

AbstractIn the yeastsSaccharomyces cerevisiaeandSchizosaccharomyces pombe, the initiation of DNA replication is controlled at a point called START. At this point, the cellular environment is assessed; only if conditions are appropriate do cells traverse START, thus becoming committed to initiate DNA replication and complete the remainder of the cell cycle. Thecdc2+/CDC28+gene, encoding the protein kinase p34, is a key element in this complex control. The identification of structural and functional homologues of p34 suggests that it has a role in the control of DNA replication in all eukaryotes. TheWHI1+,CLN1+andCLN2+gene products, identified inS. cerevisiae, are positive regulators that function at START and may interact with p34. Determining how passing the START control point leads to the initiation of DNA replication is a major outstanding challenge in cell cycle studies.