La biologia molecolare dell'eritropoietina

Molecular biology of erythropoietin. Erythropoietin (EPO) is a glycoprotein with a MW of about 30,000 Da. In adult humans, EPO is produced primarily by peritubular cells in the kidneys. The EPO gene has been found on human chromosome 7 (in band 7q21). EPO gene expression is induced by hypoxia-inducible transcription factors (HIF). It has a 165 amino acid chain with four oligosaccharide side chains and circulates in the blood at very low concentrations (~5 pmol/L). Clinical conditions that give rise to tissue hypoxia, including anaemia, lung disease or cyanotic heart disease, lead to increased concentrations of serum EPO. EPO acts by binding to a specific erythropoietin receptor (EPO-R) on the surface of red cell precursors in the bone marrow, stimulating them to transform into mature red blood cells. However, functional EPO-R have recently been demonstrated in various nonhemopoietic tissues indicating that EPO has a more pleiotropic action