Forkhead transcription factors, Fkh1p and Fkh2p, collaborate with Mcm1p to control transcription required for M-phase

Curr Biol. 2000 Jul 27-Aug 10;10(15):896-906. doi: 10.1016/s0960-9822(00)00618-7.


Background: The 'CLB2 cluster' in Saccharomyces cerevisiae consists of approximately 33 genes whose transcription peaks in late G2/early M phase of the cell cycle. Many of these genes are required for execution of the mitotic program and then for cytokinesis. The transcription factor SFF (SWI5 factor) is thought to regulate a program of mitotic transcription in conjunction with the general transcription factor Mcm1p. The identity of SFF has yet to be determined; hence further understanding of the mechanisms that regulate entry to M phase at the transcriptional level requires characterization of SFF at the molecular level.

Results: We have purified the biochemical activity corresponding to SFF and identified it as the forkhead transcription factor Fkh2p. Fkh2p assembles into ternary complexes with Mcm1p on both the SWI5 and CLB2 cell-cycle-regulated upstream activating sequence (UAS) elements in vitro, and in an Mcm1 p-dependent manner in vivo. Another closely related forkhead protein, Fkh1p, is also recruited to the CLB2 promoter in vivo. We show that both FKH1 and FKH2 play essential roles in the activation of the CLB2 cluster genes during G2-M and in establishing their transcriptional periodicity. Hence, Fkh1p and Fkhp2 show the properties expected of SFF, both in vitro and in vivo.

Conclusions: Forkhead transcription factors have redundant roles in the control of CLB2 cluster genes during the G2-M period of the cell cycle, in collaboration with Mcm1p.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cyclin B / genetics
  • Cyclin B / metabolism
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Forkhead Transcription Factors
  • Fungal Proteins / genetics
  • Fungal Proteins / isolation & purification
  • Fungal Proteins / metabolism
  • G2 Phase / genetics
  • Minichromosome Maintenance 1 Protein
  • Mitosis / genetics*
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / isolation & purification
  • Nuclear Proteins / metabolism
  • Precipitin Tests
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Transcription Factors / genetics*
  • Transcription Factors / isolation & purification
  • Transcription Factors / metabolism
  • Transcription, Genetic


  • CLB2 protein, S cerevisiae
  • Cell Cycle Proteins
  • Cyclin B
  • DNA-Binding Proteins
  • Forkhead Transcription Factors
  • Fungal Proteins
  • Minichromosome Maintenance 1 Protein
  • Nuclear Proteins
  • SWI5 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors