Serial regulation of transcriptional regulators in the yeast cell cycle

Genome-wide location analysis was used to determine how the yeast cell cycl e gene expression program is regulated by each of the nine known cell cycle transcriptional activators. We found that cell cycle transcriptional activ ators that function during one stage of the cell cycle regulate transcripti onal activators that function during the next stage. This serial regulation of transcriptional activators forms a connected regulatory network that is itself a cycle. Our results also reveal how the nine transcriptional regul ators coordinately regulate global gene expression and diverse stage-specif ic functions to produce a continuous cycle of cellular events. This informa tion forms the foundation for a complete map of the transcriptional regulat ory network that controls the cell cycle.