Ferritin serves as a storage protein for iron in animals. Complementary DNA encoding a heavy chain ferritin was cloned from the brain of Canis familiaris. The dog ferritin cDNA encodes a 182 amino acid that shows high levels of amino acid identity with vertebrate ferritins (90-98%). Near the cap region of the 5'-untranslated region, the dog H-ferritin mRNA displays a 28-nucleotide sequence that is exactly conserved in the corresponding region of the human and pig H-ferritin mRNA, thus making this sequence a prime candidate for involvement in the known translational regulation of H-ferritin by iron.