Gen K, Hirai T, Kato T, Kato Y
Institute of Endocrinology, Gunma University, Japan.
Mol Cell Endocrinol. 1994 Jul;103(1-2):101-8. doi: 10.1016/0303-7207(94)90075-2.
The existence of heterogeneous molecular species of pro-opiomelanocortin (POMC) has been reported and it has been inferred that this explains the distinct release patterns of POMC-derived peptide hormones by the anterior and intermediate lobes of the pituitary gland. The aim of this study was to determine the nucleotide sequences of porcine pituitary anterior and intermediate lobar POMC from animals of the same strain. The POMC cDNAs were obtained using immunoscreening (anterior lobe) and the polymerase chain reaction (intermediate lobe), and their nucleotide sequences determined. Comparisons of the coding and the 5'-untranslated regions of the two POMCs demonstrated that their nucleotide sequences were identical and Northern blot analysis showed that both mRNAs were the same length. Therefore, the results of this study confirm that the same POMC transcript is present in both the anterior and intermediate pituitary lobes. The differences between the nucleotide and amino acid sequences of porcine POMC found hitherto may be attributable to strain differences. Comparisons of porcine and several vertebrate POMCs revealed highly conserved amino acid sequences in the regions corresponding to the peptide hormones, but the regions between them show considerable evolutionary divergence.
已有报道指出促肾上腺皮质激素原（POMC）存在异质分子种类，据推测这解释了垂体前叶和中叶释放POMC衍生肽类激素的不同模式。本研究的目的是确定来自同一品系动物的猪垂体前叶和中叶POMC的核苷酸序列。使用免疫筛选法（前叶）和聚合酶链反应（中叶）获得POMC cDNA，并确定其核苷酸序列。对两种POMC的编码区和5'-非翻译区进行比较，结果表明它们的核苷酸序列相同，Northern印迹分析显示两种mRNA长度相同。因此，本研究结果证实垂体前叶和中叶存在相同的POMC转录本。迄今发现的猪POMC核苷酸和氨基酸序列差异可能归因于品系差异。猪与几种脊椎动物POMC的比较显示，在对应于肽类激素的区域中氨基酸序列高度保守，但它们之间的区域显示出相当大的进化差异。
