DBF2, A CELL-CYCLE-REGULATED PROTEIN-KINASE, IS PHYSICALLY AND FUNCTIONALLY ASSOCIATED WITH THE CCR4 TRANSCRIPTIONAL REGULATORY COMPLEX

CCR4, a general transcriptional regulator affecting the expression of a number of genes in yeast, forms a multi-subunit complex in vivo, Usi ng the yeast two-hybrid screen, we have identified DBF2, a cell cycle- regulated protein kinase, as a CCR4-associated protein, DBF2 is requir ed for cell cycle progression at the telophase to G(1) cell cycle tran sition, DBF2 co-immunoprecipitated with CCR4 and CAF1/POP2, a CCR4-ass ociated factor, and co-purified with the CCR4 complex, Moreover, a dbf 2 disruption resulted in phenotypes and transcriptional defects simila r to those observed in strains; deficient for CCR4 or CAF1, ccr4 and c af1 mutations, on the other hand, were found to affect cell cycle prog ression in a manner similar to that observed for dbf2 defects, These d ata indicate that DBF2 is involved in the control of gene expression a nd suggest that the CCR4 complex regulates transcription during the la te mitotic part of the cell cycle.