A Role of Corazonin Receptor in Larval-Pupal Transition and Pupariation in the Oriental Fruit Fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae).
A Role of Corazonin Receptor in Larval-Pupal Transition and Pupariation in the Oriental Fruit Fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae).
复制标题
Corazonin 受体在东方果蝇 Bactrocera dorsalis (Hendel)（双翅目：实蝇科）幼虫-蛹转变和蛹化中的作用
DOI：
10.3389/fphys.2017.00077
复制
发表时间：
2017
影响因子：
4
通讯作者：
Smagghe G
中科院分区：
文献类型：
--
作者：
Hou QL;Jiang HB;Gui SH;Chen EH;Wei DD;Li HM;Wang JJ;Smagghe G
Corazonin（Crz）是一种神经肽激素，也是一种在中枢神经系统内释放的神经肽调节剂，广泛分布于具有多种生理功能的昆虫体内。在此，我们鉴定并克隆了桔小实蝇编码Crz及其受体CrzR的cDNA。成熟的BdCrz有11个残基，具有独特的Ser 11取代（而不是典型的Asn）和在进化变量位置7的His。BdCrzR cDNA编码一个608个氨基酸的推定蛋白，具有7个推定的跨膜结构域，典型的G蛋白偶联受体的结构。当在中国仓鼠卵巢（CHO）细胞中表达时，BdCrzR对Crz表现出高灵敏度和选择性（EC 50 ≤ 52.5 nM）。利用qPCR技术，分析了B.结果表明，BdCrz和BdCrzR均在幼虫期高表达，且BdCrzR在2日龄的3龄幼虫中表达最高，表明BdCrzR可能在幼虫-蛹过渡行为中起重要作用。免疫化学定位证实了Crz在中枢神经系统（CNS）中的产生，特别是由一组三个神经元在背外侧前脑和八对侧神经元在腹神经索。qPCR分析将BdCrzR定位在CNS和气管上腺两者中，包含Inka细胞。更重要的是，dsRNA-BdCrzR介导的基因沉默导致幼虫-蛹转变和蛹化的延迟，并且这种现象与酪氨酸羟化酶和多巴脱羧酶基因的延迟表达一致。我们推测，CrzR沉默阻断多巴胺的合成，导致抑制pupariation和表皮黑化。最后，在头结扎的幼虫中注射Crz可以挽救效果。这些发现为Crz信号通路组分在B中的作用提供了新的见解。支持CrzR在幼虫-蛹转变和化蛹行为中的重要作用。
Corazonin (Crz) is a neuropeptide hormone, but also a neuropeptide modulator that is internally released within the CNS, and it has a widespread distribution in insects with diverse physiological functions. Here, we identified and cloned the cDNAs of Bactrocera dorsalis that encode Crz and its receptor CrzR. Mature BdCrz has 11 residues with a unique Ser11 substitution (instead of the typical Asn) and a His in the evolutionary variable position 7. The BdCrzR cDNA encodes a putative protein of 608 amino acids with 7 putative transmembrane domains, typical for the structure of G-protein-coupled receptors. When expressed in Chinese hamster ovary (CHO) cells, the BdCrzR exhibited a high sensitivity and selectivity for Crz (EC50 ≈ 52.5 nM). With qPCR, the developmental stage and tissue-specific expression profiles in B. dorsalis demonstrated that both BdCrz and BdCrzR were highly expressed in the larval stage, and BdCrzR peaked in 2-day-old 3rd-instar larvae, suggesting that the BdCrzR may play an important role in the larval-pupal transition behavior. Immunochemical localization confirmed the production of Crz in the central nervous system (CNS), specifically by a group of three neurons in the dorso-lateral protocerebrum and eight pairs of lateral neurons in the ventral nerve cord. qPCR analysis located the BdCrzR in both the CNS and epitracheal gland, containing the Inka cells. Importantly, dsRNA-BdCrzR-mediated gene-silencing caused a delay in larval-pupal transition and pupariation, and this phenomenon agreed with a delayed expression of tyrosine hydroxylase and dopa-decarboxylase genes. We speculate that CrzR-silencing blocked dopamine synthesis, resulting in the inhibition of pupariation and cuticular melanization. Finally, injection of Crz in head-ligated larvae could rescue the effects. These findings provide a new insight into the roles of Crz signaling pathway components in B. dorsalis and support an important role of CrzR in larval-pupal transition and pupariation behavior.