G1-specific cyclins: in search of an S-phase-promoting factor

Trends Genet. 1991 Mar;7(3):95-9. doi: 10.1016/0168-9525(91)90279-Y.


In budding yeast, Saccharomyces cerevisiae, the two principal cell cycle transitions, from G1 to S phase and from G2 to M phase, are controlled by the same protein from G2 to M phase, are controlled by the same protein kinase, CDC28, a homolog of the cdc2 protein kinase in fission yeast and other organisms. The G1 to S phase activity of the kinase is associated with accumulation of a novel family of G1 cyclins, distinct from cyclins that are required to activate the kinase for G2 to M phase functions. It remains to be determined whether G1 cyclins with similar functions exist in higher cells.

Publication types

  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • CDC2-CDC28 Kinases
  • Cell Cycle*
  • Cyclins / chemistry
  • Cyclins / genetics
  • Cyclins / metabolism*
  • Genes, Fungal
  • Humans
  • Molecular Sequence Data
  • Protein Kinases / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / growth & development*


  • Cyclins
  • Protein Kinases
  • CDC2-CDC28 Kinases