The Copeland Lab studies many aspects of selenium biology. As an essential trace element, selenium provides the core of redox balance for all vertebrates, and it does so as the "21st" amino acid, selenocysteine. Selenocysteine is incorporated into protein via a highly modified protein synthesis process, that requires multiple novel factors. Zebrafish is a great model for the system with a high degree of overlap with the human selenoproteome. We are mainly focused on mechanistic questions regarding how selenoprotein synthesis is regulated in a tissue and condition-specific manner.