Cell cycle checkpoints rConceptofbio Biology Diagrams Cell cycle checkpoints secure ordered progression from one cell cycle phase to the next. They are important to signal cell stress and DNA lesions and to stop cell cycle progression when severe problems occur. Recent work suggests, however, that the cell cycle control machinery responds in more subtle and sophisticated ways when cells are faced with naturally occurring challenges, such as This process allows cells to re-enter the cell cycle and continue proliferating despite the presence of a limited number of unrepaired lesions. This process was initially described in Saccharomyces cerevisiae by Toczyski and Hartwell in 1997. 2 More recently, checkpoint adaptation has been observed in higher organisms -including humans- and
Author summary Cell proliferation can be arrested by stimuli that disrupt key events of cell division. To protect themselves from faulty replication, cells in such conditions avoid completing cell division but stall at specific stages of the cell cycle. We investigated the consequences of prolonged but transient stalling in mitosis. We show that cells become prone to undergo errors in
TOP2A inhibition and its cellular effects related to cell cycle ... Biology Diagrams
Cell cycle checkpoints are surveillance mechanisms that monitor the order, integrity, and fidelity of the major events of the cell cycle. These include growth to the appropriate cell size, the replication and integrity of the chromosomes, and their accurate segregation at mitosis. Many of these mech โฆ Cell cycle checkpoints are surveillance mechanisms that monitor the order, integrity, and fidelity of the major events of the cell cycle. These include growth to the appropriate cell size, the replication and integrity of the chromosomes, and their Adaptation to the DNA damage checkpoint is a phenomenon long thought to be confined to the unicellular world. A new report in this issue of Cell by Yoo and colleagues (2004) suggests the presence of a checkpoint adaptation pathway in Xenopus egg extracts that displays interesting molecular parallels to adaptation in yeast.
Here, I discuss the current evidence for checkpoint adaptation in human cells and possible mechanisms and implications of this phenomenon.
Cell cycle regulation by checkpoints Biology Diagrams
Most cells that undergo G2/M-phase checkpoint adaptation (hereafter called checkpoint adaptation) after treatment with a genotoxic agent die in mitosis. However, a small number of those cells survive, and are likely to have extensively altered genomes due to the processes of repair and adaptation [6, 8].
