Martens G J
Eur J Biochem. 1987 Jun 1;165(2):467-72. doi: 10.1111/j.1432-1033.1987.tb11462.x.
This study reports the isolation and characterization of the entire proopiomelanocortin (POMC) gene of the amphibian Xenopus laevis. The Xenopus POMC gene consists of three exons of which the main exon 3 codes for all of the bioactive domains of the precursor protein. Intron A (2.6 kb) separates the segments encoding the 5'-untranslated mRNA region and intron B (2.5 kb) interrupts the protein-coding sequence near the signal peptide coding region. In that this structural organization of the Xenopus POMC gene is similar to those of the mammalian genes, apparently the POMC gene has been remarkably stable during 350 million years of vertebrate evolution. A comparative analysis of the 5'-flanking sequences of the Xenopus and mammalian POMC genes reveals the presence of several conserved regions. One of these regions is homologous with sequences located upstream of the capping sites of other glucocorticoid-regulated genes and another region contains a segment reminiscent of a viral enhancer consensus sequence.
本研究报告了两栖动物非洲爪蟾促肾上腺皮质激素原（POMC）基因全序列的分离与特性分析。非洲爪蟾POMC基因由三个外显子组成，其中主要的外显子3编码前体蛋白的所有生物活性结构域。内含子A（2.6 kb）分隔编码5'-非翻译mRNA区域的片段，内含子B（2.5 kb）在信号肽编码区域附近中断蛋白质编码序列。鉴于非洲爪蟾POMC基因的这种结构组织与哺乳动物基因相似，显然POMC基因在3.5亿年的脊椎动物进化过程中一直非常稳定。对非洲爪蟾和哺乳动物POMC基因5'-侧翼序列的比较分析揭示了几个保守区域的存在。其中一个区域与其他糖皮质激素调节基因帽位点上游的序列同源，另一个区域包含一段让人联想到病毒增强子共有序列的片段。
