Learn More
'Checkpoint' controls ensure that the events of the cell cycle are completed in an orderly fashion. For example, such controls delay mitosis until DNA synthesis and repair of radiation-induced DNA damage are complete. The rad series of radiosensitive fission yeast mutants was examined to identify strains deficient for the DNA damage-responsive checkpoint(More)
Cellular feedback or 'checkpoint' mechanisms maintain the order of completion of essential, cell-cycle related functions. In the budding yeast, for example, the RAD9 gene product is required to delay progression into mitosis in response to DNA damage. Similarly, in fission yeast, the cdc25 and cdc2 gene products influence the ability of cells to delay(More)
The cell cycle is regulated by pathways composed of a dependent series of steps, by timers, and by checkpoint controls which ensure the completion of one event before the initiation of another. This review focuses on the regulation of the initiation of mitosis, with particular emphasis on the regulation of p34cdc2 activity at this point in the cell cycle.(More)
PURPOSE To review observations of the effects of ionizing radiation on DNA synthesis in eukaryotes. CONTENT Available information broadly falls into two categories: descriptions of the phenomenon, including dose response data and analysis; and, more recently, investigations utilizing genetic approaches. The down-regulation of DNA replication in the(More)
A large number of studies have been undertaken in an attempt to define the mechanism by which caffeine (1,3,7-trimethylxanthine) reduces the duration of radiation-induced arrest of cells in the G2 phase of the cell cycle. These studies are summarized and those agents which mimic the action of caffeine are listed in the order of their potency. This ranking(More)
Radiation-induced mitotic delay is under investigation in the fission yeast, Schizosaccharomyces pombe. A large range of cell cycle- and radiation-sensitive mutants of this yeast is available to facilitate this effort. Through an examination of such mutants it has been shown that the X-ray transition point and the p34cdc2 execution point are coincident;(More)
A number of important molecular checkpoints are believed to control the orderly progression of cell cycle events. We have found that the radiation-sensitive Schizosaccharomyces pombe mutant rad3-136 is deficient in two molecular checkpoint functions. Unlike wild-type cells, the mutant cells are unable to arrest in the G2 phase of the cell cycle after DNA(More)
  • Roy Rowley
  • International journal of radiation biology and…
  • 1985
Protein synthesis is normally required for G2-cell progression and for recovery from radiation-induced G2-arrest. In the presence of 5 mM caffeine this requirement is alleviated, indicating that the mechanism responsible for G2 cell progression actually remains intact in irradiated or protein synthesis inhibitor-treated cells. It is suggested that both(More)
Filter elution was used to compare X-ray-induced DNA single- and double-strand breaks in proliferating (P) and quiescent (Q) cells of the 66 and 67 mouse mammary tumor lines. There was no difference either between cell type or between growth states in the amount of single-strand breaks as defined by elution at pH 12.2. In contrast, Q cells appeared to(More)
In the presence of 5 mM caffeine, irradiated (1.5 Gy) S and G2 cells progressed to mitosis in register and without arrest in G2. Caffeine (5 mM) markedly reduced mitotic delay even after radiation doses up to 20 Gy. When caffeine was removed from irradiated (1.5 Gy) and caffeine-treated cells, a period of G2 arrest followed, similar in length to that(More)