Delayed phosphate starvation response in cells with abundant high-affinity transporters

Wild-type cells and cells with abundant high-affinity transporters (PHO84C) were transferred from rich medium (SD) to medium containing 0.5mM phosphate Cells were grown to logarithmic phase in SC medium (OD=0.5), washed and then incubated in SC medium with intermediate phosphate level (0.5mM, initial OD=0.05). During the experiment (0, 1, 5, 8 and 23 hours) cells were harvested, pelleted and frozen for further analysis. Total RNA was extracted using MasterPure™fication Kit (Epicentre). The samples were amplified, labeled, hybridized to yeast dual color expression microarrays and scanned, all using standard Agilent protocols, reagents, and instruments. The scanned images were analyzed using SpotReader software (Niles Scientific).