昆虫鞣化激素及其受体研究进展
Progress in research on insect bursicon and its receptor
弓慧琼；赵小明； 郭东龙；马恩波；张建珍
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DOI：10.7679/j.issn.2095-1353.2018.043
作者单位：1. 山西大学生命科学学院，太原 030006；2. 山西大学应用生物学研究所，太原 030006
中文关键词：昆虫蜕皮，鞣化激素，G蛋白偶联受体，鞣化，免疫反应
英文关键词： insect molt, bursicon, G-protein-coupled receptor, tanning, immune response
中文摘要：
昆虫通过多种激素调控蜕皮过程，以完成生长发育。鞣化激素与其受体结合，调节昆虫表皮发育及鞣化、翅的伸展和成熟、肌肉收缩、卵子边缘细胞的迁移等，对昆虫的生长发育具有重要作用。鞣化激素由两个亚基（BURS和PBURS）构成，主要在胸腹神经节中合成，两个亚基在结构及其进化上较为保守，氨基酸序列中均含有11个半胱氨酸残基，在某些特定的组织中具有独立的生物学活性。鞣化激素受体为G蛋白偶联受体（G protein coupled receptor，GPCR）亚家族成员，富含亮氨酸重复序列，被命名为dLGR2。LGR2的C端区域（含多个丝氨酸残基）和N端区域（富含亮氨酸重复结构域）对于其行使正常功能具有重要作用。鞣化激素释放至血淋巴中与LGR2结合，激活cAMP/PKA信号，使酪氨酸羟化酶（Tyrosinehydroxylase，TH）磷酸化，磷酸化的TH将酪氨酸（Tyrosine）羟化为多巴（DOPA），进而引起表皮的黑化和硬化过程。另外，昆虫鞣化激素亚基形成的同源二聚体可激活转录因子Relish，调控免疫反应。本文结合近年来该领域研究成果，对鞣化激素及其受体的分子结构特性和时空表达进行分析，同时，对其在翅的延展和成熟、表皮黑化和硬化以及免疫等方面的功能研究进展进行综述，为深入认识昆虫鞣化激素及其受体作用机制提供参考。
英文摘要：
Molting in insects is regulated by a variety of hormones that regulate different stages of growth and development. Bursicon binding to its receptor regulates a variety of processes, including the development and hardening of the cuticle, wing expansion and maturation, muscle contraction and migration of the edge of the egg cell, which are of great significance to the growth and development of insects. Bursicon consists of two subunits (BURS and PBURS) and is mainly synthesized in the thoracic and abdominal ganglions, which have independent biological activity in certain situations. The structure and evolution of the two subunits are conserved and their amino acid sequences have 11 cysteine residues. The bursicon receptor is a member of the G protein coupled receptor (GPCR) subfamily, which is rich in repeat leucine sequences and is named dLGR2. The C-terminal (containing multiple serine residues) and N-terminal regions (leucine-rich repetitive structure domain) of LGR2 play an important role in the exercise of normal functions. Bursicon is released into the haemolymph where it combines with LGR2 to activate the cAMP/PKA signal and phosphorylates tyrosine hydroxylase (TH). The activated TH transforms tyrosine into dopamine (DOPA), resulting in insect cuticle sclerotization and maturation. In addition, bursicon subunits can form a homologous dimer that activates the transcription factor Relish to regulate the immune response. This paper summarizes recent research on the molecular structure of bursicon and its receptor, its temporal and spatial expression, and its role in wing expansion and hardening, cuticle sclerotization and maturation, and the immune response. This review will provide a reference for further study of the role of bursicon in insects.