Fig 4.
Grx3/4p are required for the dissociation of Aft1p from DNA in response to iron. (A) Grx3/4p are required for the iron-dependent dissociation of Aft1p from the FET3 promoter. BY4741 (WT), Δgrx3, Δgrx4, or Δgrx3 Δgrx4 strains carrying expression plasmids for Aft1-TAP were cultured in iron-free medium to mid-log-phase growth. Cells were cultured for an additional 30 min in the absence (−) or presence (+) of 200 μM FeSO4, and Aft1p binding to the FET3 and ACT1 promoters was detected by chromatin immunoprecipitation. (B) Iron regulon expression is not suppressed even under iron-replete conditions in the Δgrx3 Δgrx4 strain. The BY4741 (WT), Δgrx3, Δgrx4, and Δgrx3 Δgrx4 strains, or Δgrx3 Δgrx4 cells carrying expression plasmids for Grx3-TAP or Grx3-HA, were cultured as for panel A, and expression of the indicated genes was analyzed by Northern blotting.