Alteration of Copper Physiology in Mice Over - expressing the Human 2 Menkes Protein ATP 7 A

21 The Menkes protein (ATP7A) is defective in the Cu deficiency disorder, Menkes 22 disease and is an important contributor to maintenance of physiological copper homeostasis. To 23 investigate more fully the role of ATP7A, transgenic mice expressing the human Menkes gene 24 ATP7A from chicken β-actin composite promoter (CAG) were produced. The transgenic mice 25 expressed ATP7A in lung, heart, liver, kidney, small intestine and brain, but displayed no overt 26 phenotype resulting from expression of the human protein. Immunohistochemical analysis 27 revealed that ATP7A was expressed primarily in the cardiac muscle, smooth muscle of the lung, 28 distal tubules of the kidney, in the intestinal enterocytes, in patches of hepatocytes, and in the 29 hippocampus, cerebellum and choroid plexus of the brain. In 60 day and 300 day mice copper 30 concentrations were reduced in most tissues, consistent with ATP7A playing a role in copper 31 efflux. The reduction in copper was most pronounced in the hearts of older T22#2 females 32 (24%), T22#2 males (18%) and T25#5 females (23%) and in the brains of 60 day old T22#2 33 females and males (23% and 30%, respectively). 34