Maouche L, Tournamille C, Hattab C, Boffa G, Cartron J P, Chrétien S
Institut National de Transfusion Sanguine, Paris, France.
Blood. 1991 Nov 15;78(10):2557-63.
The genomic and complementary DNAs of the human erythropoietin receptor (hEpo-R) have been isolated and characterized from a genomic placental library and from two cDNA libraries prepared from bone marrow and fetal liver. The five different partial cDNAs isolated were aberrant in the predicted reading frames as compared with the Epo-R protein sequence, because all retained insert sequences that may represent splicing intermediates (three clones), cloning artifact (one clone), or a new sequence at a splice junction (one clone) of the gene. The cDNAs were used to isolate several genomic clones encompassing the complete hEpo-R gene. This gene, which encodes a 508-amino acid polypeptide chain of predicted M(r) 55,000, is organized into eight exons spread over 6 kb of DNA and exhibited a high degree of sequence homology (81.6% in the coding region) and structural organization with its murine counterpart. Primer extension analysis indicated that the transcription initiation site is located 141 bp upstream of the initiation codon. Sequence homology 320 bp upstream of the cap site was significantly lower (60%) and diverged completely further upstream as compared with the murine gene. Similarly, the human and murine sequences were largely divergent downstream of the stop codon, indicating that a strong conservation during evolution was restricted to the coding sequence of the Epo-R protein. The 320-bp region upstream of the cap site does not contain the typical TATA or CAAT boxes present in many tissue-specific genes, but does include potential binding sites for the ubiquitous Sp1 and the erythroid-specific GATA-1 trans-activating factors. These boxes are well conserved in sequence and position relative to the cap site within the promoter region of the human and murine genes, but the CACCC boxes present in the murine gene are absent in the human gene.
人类促红细胞生成素受体（hEpo - R）的基因组DNA和互补DNA已从基因组胎盘文库以及由骨髓和胎儿肝脏制备的两个cDNA文库中分离并进行了表征。与Epo - R蛋白序列相比，分离得到的五个不同的部分cDNA在预测的阅读框中存在异常，因为所有这些cDNA都保留了可能代表剪接中间体（三个克隆）、克隆假象（一个克隆）或该基因剪接连接处的新序列（一个克隆）的插入序列。这些cDNA被用于分离几个包含完整hEpo - R基因的基因组克隆。该基因编码一条预测分子量为55,000的508个氨基酸的多肽链，由八个外显子组成，分布在6 kb的DNA上，并且与其小鼠对应物表现出高度的序列同源性（编码区为81.6%）和结构组织。引物延伸分析表明转录起始位点位于起始密码子上游141 bp处。与小鼠基因相比，帽位点上游320 bp处的序列同源性显著较低（60%），并且在更上游完全 diverged。同样，人类和小鼠序列在终止密码子下游也有很大差异，这表明进化过程中的强烈保守性仅限于Epo - R蛋白的编码序列。帽位点上游320 bp的区域不包含许多组织特异性基因中存在的典型TATA或CAAT框，但确实包括普遍存在的Sp1和红细胞特异性GATA - 1反式激活因子的潜在结合位点。这些框在人类和小鼠基因启动子区域内相对于帽位点的序列和位置上都高度保守，但小鼠基因中存在的CACCC框在人类基因中不存在。
