The expression of the histone genes is regulated during the cell cycle to provide histones for nucleosome assembly during DNA replication. In budding yeast, histones H2A and H2B are expressed from divergent promoters at the HTA1-HTB1 and HTA2-HTB2 loci. Here, we show that the major activator of HTA1-HTB1 is Spt10, a sequence-specific DNA binding protein with a putative HAT domain. Spt10 binds to two pairs of UAS elements in the HTA1-HTB1 promoter: UAS1/UAS2 drive HTA1 expression and UAS3/UAS4 drive HTB1. UAS3 and UAS4 also contain binding sites for the cell cycle regulator SBF (a Swi4-Swi6 heterodimer), which overlap the Spt10 binding sites. Spt10 and SBF binding to UAS3 and UAS4 is mutually exclusive in vitro. Both SBF and Spt10 are bound in cells arrested with alpha-factor, apparently awaiting a signal to activate transcription. Soon after removal of alpha-factor, SBF initiates a small, early peak of HTA1 and HTB1 transcription, which is followed by a much larger peak due to Spt10. Both activators dissociate from the HTA1-HTB1 promoter after expression has been activated. Thus, SBF and Spt10 cooperate to control the timing of HTA1-HTB1 expression.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|