Cloning and expression analysis of the sheep ceruloplasmin cDNA

The cDNA encoding sheep ceruloplasmin (sCP) was isolated from a sheep liver cDNA library. The cDNA contig was 3530 nucleotides in length and encoded a protein of 1048 amino acids. The deduced amino acid sequence showed a high degree of conservation (87%) when compared to the human ceruloplasmin (hCP ) sequence. Northern blot analysis of sheep tissue revealed that the sheep ceruloplasmin gene (sCP) was expressed primarily in the liver, but low leve ls of mRNA were detected in the hypothalamus, spleen and uterus. No sCP mRN A was detected in the cortex, heart, intestine or kidney. Expression was no t significantly affected by hepatic copper content. Northern blot analysis of sheep liver during development demonstrated little sCP expression during fetal life, but significant levels of mRNA were observed after birth. Sign ificantly, the developmental expression pattern of sCP was closely correlat ed with that of the sheep Wilson disease gene (sATP7B), suggesting that the expression of the two genes may be coordinated to ensure that copper is su pplied to apoceruloplasmin. Overall, the structure and expression of sCP ap peared similar to other mammals, suggesting that abnormalities in CP were n ot responsible for the unusual sheep copper phenotype. (C) 1999 Elsevier Sc ience B.V. All rights reserved.