Corazonin receptor signaling in ecdysis initiation
Corazonin receptor signaling in ecdysis initiation
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DOI：
10.1073/pnas.0305291101
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发表时间：
2004-04-27
影响因子：
11.1
通讯作者：
Zitnan, D
中科院分区：
文献类型：
--
作者：
Kim, YJ;Spalovská-Valachová, I;Zitnan, D
珊瑚青素是一种高度保守的神经肽激素，广泛存在于昆虫中，但尚未与普遍公认的功能相关。在果蝇中发现科拉西林受体后，我们在六色蛾中确定了它的同源基因，作为生理研究的前奏。科拉津受体基因编码436个氨基酸，有7个跨膜区，与果蝇有共同的祖先。该受体在非洲爪哇卵母细胞(EC50约为200 PM)或中国仓鼠卵巢细胞(EC50约为75 PM)中表达时，对柯拉西林表现出很高的敏感性和选择性。Northern印迹分析定位于外周内分泌Inka细胞中的受体，Inka细胞是蜕皮前和蜕皮触发激素的来源。将科拉津注射到幼虫体内可引起这些多肽从Inka细胞中释放，从而引导性早熟和蜕皮行为。体外分离的印加细胞暴露于柯拉津(25-100 PM)可诱导蜕皮前和蜕皮触发激素分泌。用柯拉西林受体作为生物传感器，我们发现在自然蜕皮前20分钟血淋巴中柯拉西林的浓度在20-80 PM之间变化，然后在接下来的30-40分钟内下降。这些发现支持科拉津信号在蜕皮行为序列的启动中的作用。我们为Inka细胞和昆虫发育过程中潜在的中枢神经系统之间的肽介导的相互作用提出了一个模型。
Corazonin is a highly conserved neuropeptide hormone of widespread occurrence in insects yet is associated with no universally recognized function. After discovery of the corazonin receptor in Drosophila, we identified its ortholog in the moth, Manduca sexta, as a prelude to physiological studies. The corazonin receptor cDNA in M. sexta encodes a protein of 436 amino acids with seven putative transmembrane domains and shares common ancestry with its Drosophila counterpart. The receptor exhibits high sensitivity and selectivity for corazonin when expressed in Xenopus oocytes (EC50 approximate to 200 pM) or Chinese hamster ovary cells (EC50 approximate to 75 pM). Northern blot analysis locates the receptor in peripheral endocrine Inka cells, the source of preecdysis- and ecdysis-triggering hormones. Injection of corazonin into pharate larvae elicits release of these peptides from Inka cells, which induce precocious preecdysis and ecdysis behaviors. In vitro exposure of isolated Inka cells to corazonin (25-100 pM) induces preecdysis- and ecdysis-triggering hormone secretion. Using corazonin receptor as a biosensor, we show that corazonin concentrations in the hemolymph 20 min before natural preecdysis onset range from 20 to 80 pM and then decline over the next 30-40 min. These findings support the role of corazonin signaling in initiation of the ecdysis behavioral sequence. We propose a model for pepticle-mediated interactions between Inka cells and the CNS underlying this process in insect development.