Bck2 is a phase-independent activator of cell cycle-regulated genes in yeast.
During the cell division cycle of the yeast Saccharomyces cerevisiae, the G1-to-S transition depends upon the activation of two transcription factors (SBF and MBF), which are responsible for the cell cycle-regulated expression of more than 200 genes. Bck2 becomes essential in the absence of Cln3, the most upstream activator of this transcriptional program. Here we have used a genome-wide approach to elucidate the targets of Bck2. Our data indicate that Bck2 activates a selection of cell cycle-regulated genes from all cell cycle stages. In contrast, Cln3 activates only G1/S phase genes. Furthermore, Bck2 activates many genes independently of Swi6, the common component of SBF and MBF. Comparison of Bck2 targets with those of other transcription factors suggests that, in addition to SBF and MBF, Bck2 may elicit gene expression via Ste12 and Mcm1. We propose that Bck2 activates its targets by a mechanism fundamentally different from that of Cln3, and that it may be a necessary cofactor for the full expression of a subset of cell cycle-regulated genes.
Ferrezuelo
Francisco
F
Departament de Ciències Mèdiques Bàsiques, Institut the Recerca Biomèdica de Lleida, Universitat de Lleida, Lleida, Spain. ferrezuelof@cmb.udl.cat
Aldea
Martí
M
Futcher
Bruce
B
D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D016213:Cyclins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D026341:Minichromosome Maintenance 1 Protein; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
C082733:BCK2 protein, S cerevisiae; C079895:CLN3 protein, S cerevisiae; D018797:Cell Cycle Proteins; D016213:Cyclins; D047908:Intracellular Signaling Peptides and Proteins; C083209:MBP1 protein, S cerevisiae; C498030:MCM1 protein, S cerevisiae; D026341:Minichromosome Maintenance 1 Protein; C081540:SBF protein, S cerevisiae; C489241:STE12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors