| Title: | Evidence that a free-running oscillator drives G1 events in the budding yeast cell cycle |
| Address: | "Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 94303, USA" |
| ISSN/ISBN: | 0028-0836 (Print) 0028-0836 (Linking) |
| Abstract: | "In yeast and somatic cells, mechanisms ensure cell-cycle events are initiated only when preceding events have been completed. In contrast, interruption of specific cell-cycle processes in early embryonic cells of many organisms does not affect the timing of subsequent events, indicating that cell-cycle events are triggered by a free-running cell-cycle oscillator. Here we present evidence for an independent cell-cycle oscillator in the budding yeast Saccharomyces cerevisiae. We observed periodic activation of events normally restricted to the G1 phase of the cell cycle, in cells lacking mitotic cyclin-dependent kinase activities that are essential for cell-cycle progression. As in embryonic cells, G1 events cycled on schedule, in the absence of S phase or mitosis, with a period similar to the cell-cycle time of wild-type cells. Oscillations of similar periodicity were observed in cells responding to mating pheromone in the absence of G1 cyclin (Cln)- and mitotic cyclin (Clb)-associated kinase activity, indicating that the oscillator may function independently of cyclin-dependent kinase dynamics. We also show that Clb-associated kinase activity is essential for ensuring dependencies by preventing the initiation of new G1 events when cell-cycle progression is delayed" |
| Keywords: | "CDC28 Protein Kinase, S cerevisiae/metabolism Cyclin B/physiology Cyclin-Dependent Kinases/metabolism Cyclins/physiology DNA Replication DNA, Fungal/biosynthesis Fungal Proteins/physiology G1 Phase/*physiology Periodicity Saccharomycetales/genetics/metabo;" |
| Notes: | "MedlineHaase, S B Reed, S I eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. England 1999/10/12 Nature. 1999 Sep 23; 401(6751):394-7. doi: 10.1038/43927" |
