To address Perk function in a mouse model of metastatic melanoma [58], we generated Tyr-Cre/BrafV600ECA/+/Fbxo4mt/Perkf/f or Tyr-Cre/BrafV600ECA/+/Fbxo4mt/Perkf/+ permitting inducible activation of BrafV600E and deletion of one or two alleles of Perk in melanocytes upon application of 4-OHT. The gene discussed is EIF2AK3; the disease is metastatic melanoma.