NGFFFamide and echinotocin: structurally unrelated myoactive neuropeptides derived from neurophysin-containing precursors in sea urchins
NGFFFamide and echinotocin: structurally unrelated myoactive neuropeptides derived from neurophysin-containing precursors in sea urchins
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DOI：
10.1242/jeb.027599
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发表时间：
2009-04-15
影响因子：
2.8
通讯作者：
Rowe, Matthew L.
中科院分区：
文献类型：
--
作者：
Elphick, Maurice R.;Rowe, Matthew L.
肌动神经肽NGIWYAME最初是从海参刺参中分离出来的，但有证据表明，NGIWYAME样肽也存在于其他棘皮动物中。在这里，我们报道了在紫球海胆中发现的一个基因，它编码两个拷贝的NGIWYAME样肽：ASN-Gly-Phe-(NH(2))或NGFFamide。有趣的是，NGFFamide前体的C末端区域与神经内分泌蛋白有相似的序列，神经内分泌蛋白是迄今为止唯一与血管加压素/催产素样神经肽前体相关的载体蛋白。因此，NGFFamide前体是第一个被发现的不包含加压素/催产素样肽的含有神经物理素神经肽的前体。然而，神经物理素是否作为NGFFFamide的载体蛋白仍有待确定。紫斑沙门氏菌基因组还包含一个编码前体的基因，该前体包括一种神经物理素多肽和‘棘球菌素’(CFISNCPKG)--这是在棘皮动物中发现的第一个血管加压素/催产素样肽。因此，在紫毛链霉菌中，有两个基因编码前体，这两个基因具有神经物理蛋白结构域，但编码结构上无关的神经肽。此外，NGFFamide和棘球菌素都能引起海胆的管脚和食道的收缩，这与海参中NGIWYAME的肌活性和其他动物门中的加压素/催产素样多肽的肌活性一致。据推测，NGFFamide前体在部分或完全复制编码血管加压素/催产素样肽的基因后获得了其神经物理蛋白结构域，但在进化史上何时发生仍有待确定。
The myoactive neuropeptide NGIWYamide was originally isolated from the holothurian (sea cucumber) Apostichopus japonicus but there is evidence that NGIWYamide-like peptides also occur in other echinoderms. Here we report the discovery of a gene in the sea urchin Strongylocentrotus purpuratus that encodes two copies of an NGIWYamide-like peptide: Asn-Gly-Phe-Phe-Phe-(NH(2)) or NGFFFamide. Interestingly, the C-terminal region of the NGFFFamide precursor shares sequence similarity with neurophysins, carrier proteins hitherto uniquely associated with precursors of vasopressin/oxytocin-like neuropeptides. Thus, the NGFFFamide precursor is the first neurophysin-containing neuropeptide precursor to be discovered that does not contain a vasopressin/oxytocin-like peptide. However, it remains to be determined whether neurophysin acts as a carrier protein for NGFFFamide. The S. purpuratus genome also contains a gene encoding a precursor comprising a neurophysin polypeptide and 'echinotocin' (CFISNCPKGamide)-the first vasopressin/oxytocin-like peptide to be identified in an echinoderm. Therefore, in S. purpuratus there are two genes encoding precursors that have a neurophysin domain but which encode neuropeptides that are structurally unrelated. Furthermore, both NGFFFamide and echinotocin cause contraction of tube foot and oesophagus preparations from the sea urchin Echinus esculentus, consistent with the myoactivity of NGIWYamide in sea cucumbers and the myoactivity of vasopressin/oxytocin-like peptides in other animal phyla. Presumably the NGFFFamide precursor acquired its neurophysin domain following partial or complete duplication of a gene encoding a vasopressin/oxytocin-like peptide, but it remains to be determined when in evolutionary history this occurred.