Recombinant Human Erythropoietin R Fc Chimera Protein, CF

Erythropoietin (EPO), a glycoprotein produced primarily by the kidney, is the principal factor that regulates erythropoiesis by stimulating the proliferation and differentiation of erythroid progenitor cells. The biological effects of EPO are mediated by the erythropoietin receptor (EPO R). The genes for human and mouse EPO R have been cloned and characterized. The full-length human EPO R cDNA encodes a type I membrane-spanning protein with 508 amino acid (aa) residues (a 24 aa residue hydrophobic signal sequence, a 226 aa residue extracellular domain, a 22 aa residue transmembrane domain and a 236 aa residue cytoplasmic domain). At the protein sequence level, the human EPO R is approximately 82% identical to the mouse protein. As a result of alternative splicing of the EPO R gene, cDNA clones encoding a truncated form of the EPO R as well as a soluble form of EPO R has been found. The presence of a soluble form of the EPO R has also been detected in human sera. Recombinant soluble EPO R binds EPO with high affinity and is a potent EPO antagonist.