Fig. 6. Cell-cycle regulation of the rblA promoter. Wild-type cells bearing the rblA::pgal reporter were synchronized by cold shock. Over an 8-hour period, reporter activity was followed using chemoluminescence, nuclear DNA synthesis was monitored by BrdU pulse-labeling and cell number measured using a Coulter counter. Gal activities in RLU/µg protein and BrdU incorporation in percent of total nuclei were normalized to the respective average over the entire experiment.