The MTF1:zinc complex in the nucleus binds Metal Response Elements (MREs), DNA containing the core consensus sequence 5'-TGCRCNC-3', and activates or represses transcription depending on the context of the MRE (reviewed in Laity and Andrews 2007, Jackson et al. 2008, Gunther et al. 2012, Grzywacz et al. 2015). The 6 zinc fingers of each MTF1 monomer have different affinities for zinc and evidence from the mouse homolog indicates that different concentrations of zinc, and hence different metal loads in MTF1, activate different subsets of target genes (Wang et al. 2004, Dong et al. 2015). Genes activated by MTF1 include those encoding metallothioneins, zinc transporters, and stress-response proteins (Hardyman et al. 2016).