Promiscuity rules? The dispensability of cyclin E and Cdk2.
The canonical view of the mammalian cell cycle arose from studies of cultured cells rather than mutant organisms. It depicts the many complexes of cyclin and Cdk (cyclin/Cdk) as fulfilling unique and essential steps that dictate the sequential order of cell cycle events. Recent analyses of knockout mice challenge this view. Cdk2 and cyclin E, long thought to be essential, are largely dispensable. Here, we discuss the phenotypes of these and other cyclin/Cdk mutants in genetically tractable metazoa (mouse, fly, and nematode) and explore possible reasons behind similarities and differences among experimental systems and cell types.
Su
Tin Tin
TT
MCD Biology, University of Colorado, Boulder, CO 80309-0347, USA. tin.su@colorado.edu
Stumpff
Jason
J
D000818:Animals; D042846:CDC2-CDC28 Kinases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D002453:Cell Cycle / Q000502:physiology*; D002478:Cells, Cultured; D019927:Cyclin E / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D004261:DNA Replication; D005314:Embryonic and Fetal Development / Q000502:physiology; D018390:Gene Targeting; D006801:Humans; D007448:Invertebrates / Q000235:genetics / Q000378:metabolism; D046911:Macromolecular Substances; D008322:Mammals / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008954:Models, Biological; D010641:Phenotype; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D016160:Retinoblastoma Protein / Q000502:physiology; D016196:S Phase / Q000502:physiology; D013379:Substrate Specificity
D019927:Cyclin E; D046911:Macromolecular Substances; D016160:Retinoblastoma Protein; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases