Cloning of the human erythropoietin receptor gene

We have isolated and characterized a genomic clone of the human erythropoietin (Epo) receptor from a placental genomic library using a cDMA probe for the murine Epo receptor. The coding region spans about 6.5 kb with seven intervening sequences ranging in size from 81 bp to 2.1 kb. A stretch of 123 purines is found in the 5' region from -456 to -578 upstream from the first codon and flanking the Alu repetitive sequences located further upstream. The human Epo receptor contains a palindromic sequence 5′ of the translated region that consists of an almost perfect inverted repeat of 12 nucleotides (CAGCTGC(G/C)TCCG) centered about G at -92 from the first codon. An inverted SP1 binding site (CCGCCC) and an inverted GATA-1 binding site (TTATCT) are located at positions -151 and -179, respectively, and CACCC sequences are located at -585 and further upstream. No TATA or CAAT sequences are in this 5′ flanking region. However, this region as far as -275 has a 72% GC content compared with an overall GC content of 56%. A 1-kb SamHl fragment of the human Epo receptor containing 700 bp of sequences 5′ of the coding region was transcribed in an in vitro transcription assay; initiation of transcription appeared to be around 132 ± 5 just downstream from the inverted SP1 site at -151. T1 analysis of human Epo receptor messenger RNA also maps the site of transcription initiation to this region. Within 180 nucleotides 5′ to the first exon are three regions with 70% or greater homology with the murine Epo receptor. The study of this gene, including its similarities with the murine Epo receptor, should help elucidate aspects of the transcriptional and possible translational control of the Epo receptor in human erythroid cells and thus its role in signal transduction and erythroid differentiation.