Ixr1 regulates RNR1 promoter activity.

(A) β-Galactosidase assay of RNR1, RNR3, and RNR4 promoter activity in wild-type (W1588-4C) and ixr1Δ (TOY736) strains. Promoters of the analyzed genes were fused with the lacZ repoter gene and the respective plasmids were transformed in the wild type and ixr1Δ strains. β-Gal units were quantified as described in Materials and Methods. (B) Analysis of DNA associated with Ixr1 was performed by chromatin immunoprecipitation (ChIP) followed by qPCR using locus-specific primers for the RNR1 promoter (pRNR1), the DSF2 promoter (pDSF2) and the ACT1 gene. ChIP was performed with IXR1 (W1588-4C) and IXR1-9MYC (TOY836) strains using anti-Myc antiserum 9E10 or mock-antiserum. For pRNR1, ChIP was performed both without and with addition of 4-NQO (0.2 mg/L). Y axis represents the amount of precipitated DNA relative to the input DNA. Values shown are the average from two independent experiments with the minimum and maximum values represented.