Interferon-alpha, also known as leukocyte interferon, comprises a group of related but distinct proteins that share over 95% amino acid sequence homology. They are members of the type I interferon family which share a common cell surface receptor composed of two subunits, a 100 kDa ligand-binding subunit (IFN-alpha R1) and a 125 kDa subunit (IFN-alpha R2) that is involved both in ligand-binding and signal transduction. IFN-alpha is expressed primarily by leukocytes upon activation by viruses, bacteria, cytokines and growth factors. IFN-alpha has been shown to have anti-viral and immunomodulatory activities on target cells. It can also inhibit cell proliferation as well as induce apoptosis (1, 2).
Cotton rat IFN-alpha 1 cDNA encodes a 189 amino acid (aa) residue precursor protein with a putative 23 aa signal sequence and a 166 aa mature protein. The protein contains five cysteines, four of which are involved in two intrachain disulfide bonds. Cotton rat IFN-alpha 1 shares 52%, 67%, 68% and 72% aa sequence identity to human, rat, hamster and mouse IFN-alpha 1, respectively.
