The zinc finger transcription factor MTF-1 (metal-responsive transcription factor-1) is conserved from insects to vertebrates. The major role of MTF-1 in both organisms is to control the transcription of genes involved in the homeostasis and detoxification of heavy metal ions such as Cu2+, Zn2+ and Cd2+. In mammals, MTF-1 serves at least two additional roles. First, targeted disruption of the MTF-1 gene results in death at embryonic day 14 due to liver degeneration, revealing a stage-specific developmental role. Second, under hypoxic-anoxic stress, MTF-1 helps to activate the transcription of the gene placental growth factor (PIGF), an angiogenic protein.