A systematic screen reveals new elements acting at the G2/M cell cycle control
1 Cell Cycle Lab. Cancer Research UK-London Research Institute, Lincoln's Inn Fields 44, London WC2A 3LY, UK
2 Laboratory of Yeast Genetics and Cell Biology, The Rockefeller University, York Avenue 1230, New York 10065, USA
3 Francis Crick Institute, Euston Road 215, London, NW1 2BE, UK
Genome Biology 2012, 13:R36 doi:10.1186/gb-2012-13-5-r36Published: 24 May 2012
The major cell cycle control acting at the G2 to mitosis transition is triggered in all eukaryotes by cyclin-dependent kinases (CDKs). In the fission yeast Schizosaccharomyces pombe the activation of the G2/M CDK is regulated primarily by dephosphorylation of the conserved residue Tyr15 in response to the stress-nutritional response and cell geometry sensing pathways. To obtain a more complete view of the G2/M control we have screened systematically for gene deletions that advance cells prematurely into mitosis.
A screen of 82% of fission yeast non-essential genes, comprising approximately 3,000 gene deletion mutants, identified 18 genes that act negatively at mitotic entry, 7 of which have not been previously described as cell cycle regulators. Eleven of the 18 genes function through the stress response and cell geometry sensing pathways, both of which act through CDK Tyr15 phosphorylation, and 4 of the remaining genes regulate the G2/M transition by inputs from hitherto unknown pathways. Three genes act independently of CDK Tyr15 phosphorylation and define additional uncharacterized molecular control mechanisms.
Despite extensive investigation of the G2/M control, our work has revealed new components of characterized pathways that regulate CDK Tyr15 phosphorylation and new components of novel mechanisms controlling mitotic entry.