Many cell-cycle-specific events are supported by stage-specific gene expression. In budding yeast, at least three different nuclear factors seem to cooperate in the periodic activation of G2/M-specific genes(1-3). Here we show, by using chromatin immunoprecipitation polymerase chain reaction assays, that a positive regulator, Ndd1, becomes associated with G2/M promoter regions in manner that depends on the stage in cell cycle. Its recruitment depends on a permanent protein-DNA complex consisting of the MADS box protein, Mcm1, and a recently identified partner Fkh2, a forkhead/winged helix related transcription factor(4,5). The lethality of Ndd1 depletion is suppressed by fkh2 null mutations, which indicates that Fkh2 may also have a negative regulatory role in the transcription of G2/M-induced RNAs. We conclude that Ndd1-Fkh2 interactions may be the transcriptionally important process targeted by Cdk activity.
