title: Negative regulation of mitosis by wee1+, a gene encoding a protein kinase homolog.
abstract: Fission yeast wee1- mutants initiate mitosis at half the cell size of wild type. The wee1+ activity is required to prevent lethal premature mitosis in cells that overproduce the mitotic inducer cdc25+. This lethal phenotype was used to clone wee1+ by complementation. When wee1+ expression is increased, mitosis is delayed until cells grow to a larger size. Thus wee1+ functions as a dose-dependent inhibitor of mitosis, the first such element to be specifically identified and cloned. The carboxy-terminal region of the predicted 112 kd wee1+ protein contains protein kinase consensus sequences, suggesting that negative regulation of mitosis involves protein phosphorylation. Genetic evidence indicates that wee1+ and cdc25+ compete in a control system regulating the cdc2+ protein kinase, which is required for mitotic initiation.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D005796:Genes; D005800:Genes, Fungal; D005804:Genes, Lethal; D005809:Genes, Regulator; D008938:Mitosis; D011494:Protein Kinases / Q000235:genetics*; D004718:Saccharomycetales / Q000235:genetics*; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D011494:Protein Kinases; D004262:DNA Restriction Enzymes