Structure of promoter region in the 5' upstream of neurohypophysial hormone genes in salmon

本文报道了鲑科鱼类神经垂体激素前体分子基因组DNA的结构、5'上游启动子区的核苷酸序列以及根据cDNA序列构建的脊椎动物神经垂体激素前体分子系统进化树。由于鲑科动物是四倍体，它们具有两种（I和II）前体，分别用于催产素（VT）和异催产素（IT）。本研究仅对VT-Ⅰ和IT-Ⅰ前体进行了分析，VT-Ⅰ基因有两个内含子和三个外显子，第一个外显子有5'端非翻译区。这种结构基本上与哺乳动物血管树脂基因的结构相同。与鲑鱼VT和哺乳动物vasopresin的5'非翻译区的比较显示，在启动子区中调节元件的不同组织。鲑鱼与哺乳动物的其他区别在于：鲑鱼中只有一个AP-2，而哺乳动物中有大量AP-2。在鲑鱼中有几个CAT盒，而在哺乳动物中很少。一个 ...更多信息 鲑鱼IT-I基因与哺乳动物催产素基因一样，具有2个内含子和3个外显子，但哺乳动物催产素基因中不存在ERE。有趣的是，用Southern杂交方法证明白色吸盘的IT基因不含内含子。根据脊椎动物神经垂体激素前体基因cDNA的核苷酸序列，构建了脊椎动物神经垂体激素前体基因的系统发育树，并采用相邻连接法和最大似然法计算了遗传距离。本树与Hyodo等人报道的树不同，1991年，部分地区。一个大的分歧首先发生在共同的祖先神经垂体激素的脊椎动物，即分叉成四足动物和硬骨鱼类。四足动物群进一步分为两组，蟾蜍VT组和包括蟾蜍中催产素、哺乳动物血管紧张素和催产素的促性腺激素组。催产素和加压素都与蟾蜍中催产素有共同的祖先分子。综上所述，本研究揭示了硬骨鱼类神经垂体激素基因前体区与其他脊椎动物有不同的结构。根据氨基酸序列和基因组DNA结构，提出了一种新的神经垂体激素进化树。少

We report the structure of genomic DNA of salmonid neurohypophysial hormohe precursor molecules, the nucleotide sequence of the promoter region in the 5' upstream of the DNA and a phylogenetic tree of neurohypophysial hormone precursors in vertebrates constructed from the cDNA sequence data. Since salmonids are tetraploid, they have two (I and II) precursors for each of vasotocin (VT) and isotocin (IT). Only VT-I and IT-I precursor were used for analysis in this study.The VT-I gene has two introns and three exsons with the 5' untranslated region on the first exon. This structure is principally the same as that of the mammalian vasopresin gene. Comparison of the 5' untranslated region with the salmon VT and mammalian vasopresin showed a different organization of regulatory elements in promoter region. The other differences between salmon and mammal were the followings : there was only one AP-2 in salmon but a lot of in mammal. There are several CAT boxes in salmon and few in mammal. An … More putative ERE exist in salmon but not in mammalian vasopresin although mammalian oxytocin gene contain an effective ERE.The salmon IT-I gene had two introns and three exsons as the well as the mammalian oxytocin gene. Interestingly, IT gene of white sucker have been shown not to contain intron by the southern hybridization method. There may be at least two types of IT genes in the teleost group.A phylogenetic tree of neurohypophysial hormone precursors in vertebrates were constructed with the sequence data of the amino acid translated from the nucleotide sequences of their cDNA.Two methods, neighbor joining and maximum liklihood, were used for the calculation of phylogenic distances. The present tree is different from the tree reported by Hyodo et al., 1991 in some portions. A large divergence first occurred in the common ancestral neurohypophysial hormone of vertebrates, i.e.bifurcation into the tetrapod and teleost tranks. The tetrapod trank was further divided into two groups, the toad VT group and group of remainers that includes toad mesotocin, mammalian vasopresin, and oxytocin. Not only oxytocin but also vasopresin had a common ancestral molecule with toad mesotocin.In summary, this study revealed the precursor region of teleost neurohypophysial hormone genes have different structures from other vertebrates. Furthermore, a new evolutionary tree of neurohypophysial hormones based on the amino acid sequence and genomic DNA structures was proposed. Less