Figure 5.

Aft2p is a direct transcriptional activator that responds to low iron. S1 nuclease protection assays were carried out by using RNA isolated from (A) the aft2Δ strain transformed with either pGAL-AFT2-1^up or pYeF2 (control), which were grown in CM(−Ura) with raffinose to mid-log phase, at which time 2% galactose was added to induce the transcription of the AFT2-1^up allele. Cells were harvested at the specified times (B), the aft1Δaft2Δ strain was transformed with pRS416 (control), pAFT2, and pAFT2-1^up, which were pregrown overnight with 10 μM FeCl₂, harvested, washed, and resuspended in CMD(−Ura) medium with or without supplemental FeCl₂ (100 μM) or BPS (100 μM) and then grown exponentially for 8 h. The Upper band for each sample is the specified gene, and the Lower band the calmodulin loading control (CMD1).