PRECURSOR POLYPROTEIN FOR MULTIPLE NEUROPEPTIDES SECRETED FROM THE SUBESOPHAGEAL GANGLION OF THE SILKWORM BOMBYX-MORI - CHARACTERIZATION OF THE CDNA-ENCODING THE DIAPAUSE HORMONE PRECURSOR AND IDENTIFICATION OF ADDITIONAL PEPTIDES
PRECURSOR POLYPROTEIN FOR MULTIPLE NEUROPEPTIDES SECRETED FROM THE SUBESOPHAGEAL GANGLION OF THE SILKWORM BOMBYX-MORI - CHARACTERIZATION OF THE CDNA-ENCODING THE DIAPAUSE HORMONE PRECURSOR AND IDENTIFICATION OF ADDITIONAL PEPTIDES
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DOI：
10.1073/pnas.90.8.3251
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发表时间：
1993-04-15
影响因子：
11.1
通讯作者：
YAMASHITA, O
中科院分区：
文献类型：
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作者：
SATO, Y;OGUCHI, M;YAMASHITA, O
肽能神经元是多种内分泌神经肽的来源，存在于昆虫的食管下神经节（SG）和脑中。家蚕SG分泌两种神经肽，即诱导胚胎滞育的滞育激素（DH）和激活信息素生物合成的神经肽，它们的C端都有一个五肽酰胺Phe-Xaa-Pro-Arg-Leu-NH_2（Xaa = Gly或Ser）。我们用寡核苷酸探针从SG的cDNA文库中分离了DH的cDNA克隆。cDNA的分子特征表明，该mRNA编码一个开放的阅读框架，由192个氨基酸残基组成，其中24-aa的DH肽定位在N-末端区域后的信号肽。同源性搜索表明，该cDNA编码信息素生物合成激活神经肽和其他三种神经肽[α-，β-和γ-SG神经肽（SGNP）]在DH后的区域，所有这些都是侧翼可能的胰蛋白酶切割位点，并在C末端共享Phe-Xaa-Pro-Arg-Leu-Gly序列。北方杂交分析清楚地表明该基因的表达仅限于SG。我们化学合成了α-，β-和γ-SGNP，并用它们来鉴定SG提取物中的组分并检查生物功能。在SG的提取物中鉴定了α-和γ-SGNP，并且合成的β-和γ-SGNP表达弱DH活性。这些结果表明，DH，沿着与其他四种神经肽，是从一个共同的前体多聚蛋白，是由一个单一的mRNA在SG的神经分泌细胞中转录编码。
Peptidergic neurons, which serve as source of various endocrine neuropeptides, were identified in the suboesophageal ganglion (SG) and brain of insects. In the silkworm Bombyx mori, SG is known to secrete two neuropeptides, diapause hormone (DH) responsible for induction of embryonic diapause and pheromone biosynthesis-activating neuropeptide, which share a pentapeptide amide, Phe-Xaa-Pro-Arg-Leu-NH2 (Xaa = Gly or Ser), at the C terminus. We have isolated cDNA clones for DH from the cDNA library of SG by using oligonucleotide probes. The molecular characterization of the cDNA reveals that the mRNA encodes an open reading frame consisting of 192 aa residues in which the 24-aa DH peptide is localized at the N-terminal region just after the signal peptide. A homology search proposed that the cDNA encodes pheromone biosynthesis-activating neuropeptide and three other neuropeptides [alpha-, beta-, and gamma-SG neuropeptide (SGNP)] in the region following DH, all of which are flanked by possible tryptic cleavage sites and share the Phe-Xaa-Pro-Arg-Leu-Gly sequence at the C terminus. Northern hybridization analysis clearly showed that the gene expression was limited to SG. We chemically synthesized alpha-, beta-, and gamma-SGNP and used them to identify components in extracts of SG and to examine biological functions. Alpha- and gamma-SGNP were identified in extracts of SG, and the synthetic beta- and gamma-SGNP expressed weak DH activity. These results indicate that DH, along with four other neuropeptides, is generated from a common precursor polyprotein that is encoded by a single mRNA transcribed in neurosecretory cells of SG.