Cadmium response of Ndrg1 depends on MTF-1. (a) Semiquantitative RT–PCRs for Ndrg1 mRNA using total liver RNA from pI–pC-induced male Mtf1Mx-cre or Mtf1loxP mice. The animals had obtained either mock s.c. injections (−Cd) or s.c. injections with 20 µmol/kg body weight CdSO4 (+Cd) 6 h before sacrificing them. RT–PCRs for Hprt mRNA were used as internal control to adjust the amount of total RNA used. (b) MRE core consensus sequences TGCRCNC (bold letters) and flanking sequences found in a region of 1000 bp upstream from Ndrg1 transcription start; the position of each core sequence is indicated. (c) EMSA with liver protein extracts of a male Mtf1loxP or a pI–pC-induced, male Mtf1Mx-cre mouse, both mock-treated. MTF-1 protein–DNA complex formation was tested with 32P-labeled Ndrg1 MRE1 or MRE2 oligonucleotide, or a 32P-labeled oligonucleotide including both MRE3 and MRE4 (MRE3,4). Specificity of binding was verified with excess of unlabeled competitor MREd or unrelated Gal4 oligonucleotide. 32P-labeled MRE-s was included to indicate the position of an MTF-1-DNA complex; Sp1 bandshifts with 32P-labeled Sp1 consensus oligonucleotide were obtained as protein loading control.