Hypoxia inducible factor-1 (HIF-1) was first discovered by Semenza et al1 in 1991 as a protein which could specifically bind to the oligonucleotide sequence of the erythropoietin gene enhancer.The dimmers of HIF-1 were isolated in the following year.As its subunits were found to be induced by hypoxic conditions,it was subsequently named as hypoxia inducible factor.2 HIF-1,commonly found in human and mammalian cells,also expressed in normoxic conditions.
