Interacting selectively and non-covalently with a sequence of DNA that is in cis with and relatively close to a core promoter for RNA polymerase II (RNAP II) and interacting selectively and non-covalently with metal ion(s) and responding, e.g. by conformational change, to changes in the cellular level of metal ion, such a way that metal ion binding regulates the activity of the transcription factor in order to stop, prevent, or reduce the frequency, rate or extent of transcription from an RNA polymerase II promoter.