Hang Xiaoming, Balment Richard John
Faculty of Life Sciences, 3.614 Stopford Building, University of Manchester, UK.
Gen Comp Endocrinol. 2005 Nov;144(2):188-95. doi: 10.1016/j.ygcen.2005.05.008. Epub 2005 Jul 21.
Stanniocalcin (STC) is a homodimeric glycoprotein hormone that was first discovered in fish, where it is largely produced by a unique endocrine gland, the corpuscles of Stannius (CS). In bony fish, it is thought to be an important regulator of calcium and phosphate uptake from the aquatic environment. This report describes the molecular cloning of STC from euryhaline flounder (Platichthys flesus) CS cDNA and genomic DNA. The flounder STC encodes a prehormone of 251 amino acids (aa) with a signal peptide of 17 aa, followed by another 15 aa sequence before the mature protein of 219 aa. The deduced aa sequence of flounder STC shows 62.9-89.0% similarity and 50.4-83.1% identity with other known fish STC sequences, but only 42.3% identity with mouse STC1, 24.4% identity with fugu and zebrafish STC2, and 22.3% identity with mouse STC2. Primary structural analysis demonstrated that flounder STC gene contains five exons in contrast to the four exons present in mammalian STC gene. RT-PCR revealed the expression of flounder STC mRNA to be widely spread in many tissues and organs, similar to the situation in mammals and other fish. Quantitative PCR (Q-PCR) was conducted to measure relative STC expression levels in the CS, which showed STC mRNA expression levels in seawater-adapted fish CS were about 3-fold higher than in freshwater-adapted fish CS.
鲽鱼降钙素（STC）是一种同型二聚体糖蛋白激素，最初在鱼类中被发现，主要由一种独特的内分泌腺——斯坦尼氏小体（CS）产生。在硬骨鱼中，它被认为是从水生环境中摄取钙和磷的重要调节因子。本报告描述了从广盐性比目鱼（欧洲比目鱼）CS cDNA和基因组DNA中克隆STC的分子过程。比目鱼STC编码一种含251个氨基酸（aa）的前激素，带有一个17个aa的信号肽，在成熟的219个aa蛋白之前还有一个15个aa的序列。推导的比目鱼STC氨基酸序列与其他已知鱼类STC序列的相似性为62.9 - 89.0%，同一性为50.4 - 83.1%，但与小鼠STC1的同一性仅为42.3%，与河豚和斑马鱼STC2的同一性为24.4%，与小鼠STC2的同一性为22.3%。一级结构分析表明，与哺乳动物STC基因中的四个外显子不同，比目鱼STC基因包含五个外显子。逆转录聚合酶链反应（RT-PCR）显示比目鱼STC mRNA在许多组织和器官中广泛表达，这与哺乳动物和其他鱼类的情况相似。进行了定量聚合酶链反应（Q-PCR）以测量CS中STC的相对表达水平，结果显示海水适应鱼CS中的STC mRNA表达水平比淡水适应鱼CS中的高约3倍。
