title: Cell cycle-regulated transcription through the FHA domain of Fkh2p and the coactivator Ndd1p.
abstract: Recent studies in Saccharomyces cerevisiae by using global approaches have significantly enhanced our knowledge of the components involved in the transcriptional regulation of the cell cycle. The Mcm1p-Fkh2p complex, in combination with the coactivator Ndd1p, plays an important role in the cell cycle-dependent expression of the CLB2 gene cluster during the G2 and M phases ([4-7]; see [8-10]for reviews). Fkh2p is phosphorylated in a cell cycle-dependent manner, and peak phosphorylation occurs coincidentally with maximal expression of Mcm1p-Fkh2p-dependent gene expression. However, the mechanism by which this complex is activated in a cell cycle-dependent manner is unknown. Here, we demonstrate that the forkhead-associated (FHA) domain of Fkh2p directs cell cycle-regulated transcription and that the activity of this domain is dependent on the coactivator Ndd1p. Ndd1p was found to be phosphorylated in a cell cycle-dependent manner by Cdc28p-Clb2p, and, importantly, this phosphorylation event promotes interactions between Ndd1p and the FHA domain of Fkh2p. Furthermore, mutation of the FHA domain blocks these phosphorylation-dependent interactions and abolishes transcriptional activity. Our data therefore link the transcriptional activity of the FHA domain with cell cycle-dependent phosphorylation of the coactivator Ndd1p and reveal a mechanism that permits precise temporal activation of the Mcm1p-Fkh2p complex.
authors.affiliation: School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, United Kingdom.
authors.forename: Zoulfia
authors.initials: Z
authors.lastname: Darieva
authors.forename: Aline
authors.initials: A
authors.lastname: Pic-Taylor
authors.forename: Joanna
authors.initials: J
authors.lastname: Boros
authors.forename: Adonis
authors.initials: A
authors.lastname: Spanos
authors.forename: Marco
authors.initials: M
authors.lastname: Geymonat
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Reece
authors.forename: Steven G
authors.initials: SG
authors.lastname: Sedgwick
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Sharrocks
authors.forename: Brian A
authors.initials: BA
authors.lastname: Morgan
mesh_terms: D015153:Blotting, Western; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D019926:Cyclin B / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D051858:Forkhead Transcription Factors; D040461:Gene Components; D008954:Models, Biological; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics*
chemical_list: C093749:CLB2 protein, S cerevisiae; D018797:Cell Cycle Proteins; D019926:Cyclin B; C464958:Fkh2 protein, S cerevisiae; D051858:Forkhead Transcription Factors; C118820:NDD1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D017489:CDC28 Protein Kinase, S cerevisiae