保幼激素在昆虫中的分子作用机理

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 保幼激素在昆虫中的分子作用机理 DOI: 10.5846/stxb201306061380 作者: 作者单位: 中国计量学院生命科学学院,中国计量学院生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划（2010CB126200） Molecular mechanisms of the insect juvenile hormone Author: Affiliation: College of Life Sciences,China Jiliang University,Provincial Key Laboratory of Biometrology and Inspection Quarantine,College of Life Sciences,China Jiliang University,Provincial Key Laboratory of Biometrology and Inspection Quarantine Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:随着分子生物学技术的快速发展，对生态环境中各类生物的研究，包括对生物某些特定基因结构和功能的研究等逐步拓展和加深。保幼激素（Juvenile Hormone，JH）是由咽侧体（Corpus Allatum，CA）分泌的，在昆虫发育、变态和生殖过程中起重要作用的激素。目前对JH信号传导途径的作用机理还不十分清楚。现有研究表明，Kruppel homolog-1（Kr-h1）是一种含C2H2锌指结构的转录因子，处于保幼激素信号途径下游，在保幼激素信号通路中起着重要作用。已报道的Kr-h1基因的功能主要包括：调控幼虫生长发育和变态，与蜜蜂的觅食行为密切相关，参与果蝇幼体神经细胞的形成等等。对就近十年来Kr-h1基因的特性和功能研究作一个综述以了解不同昆虫中保幼激素的分子作用机制，为开发生物农药奠定理论基础，也为维护良好的生态环境作出理论贡献。 Abstract:Following the rapid development of molecular biology techniques, many studies have been carried out of specific gene structures and functions, including those in ecological environments. Juvenile hormone (JH) is an important insect hormone that regulates insect larval development, reproduction, and metamorphosis, although the molecular mechanism behind this remains unclear. The transcription factor Kruppel-homolog 1(Kr-h1) acts downstream of the JH receptor and plays a key role in the JH signaling pathway. It has been identified in over 21 insect species, and sequence analysis has shown it to contain 2-8 C2H2-type zinc-finger motifs, which are highly conserved among Kr-h1 proteins. We previously found that zinc-fingers Zn2-Zn7 are more conserved than others in all insect species we compared. Interestingly, we found that the jewel wasp Nasonia vitripennis only contains two zinc-fingers, Zn4 and Zn7, while the body louse Pediculus humanus corporis contains all zinc-fingers except Zn7. As N. vitripennis and P. humanus were the only two parasitoids among the 21 insect species examined, it is possible that zinc fingers might be lost during evolution. Studies in Drosophila melanogester, Bombyx mori, Tribolium castaneum, and Frankliniella occidentalis revealed that Kr-h1 is required for embryonic development and metamorphosis, and that its down-regulation results in development of the precocious phenotype. Knockdown of Kr-h1 by RNAi in the brown planthopper Nilaparvata lugens showed that this gene is required for normal wing and external genitalia development. Kr-h1 is also involved in neuron development, the regulation of photoreceptor maturation, larval growth, insect development and metamorphosis, and the formation of Drosophila melanogaster neurons. In addition, it controls the foraging behavior of honey bees through affecting the expression of the cGMP-mediated activation of protein kinase G. The expression of Kr-h1 is induced by JH and its mimics. The Bombyx mori juvenile hormone response element (bmJHRE), located 141 bp upstream of Kr-h1, includes an E-box with the sequence CACGTG. bmJHRE was found in the genomic sequence of all seven insect species that we previously analyzed, and the E-box was highly conserved in all species (100%). The E-boxes of Tribolium castaneum Kr-h1(TcKr-h1) and Apis mellifera Kr-h1(AmKr-h1) are close to the Kr-h1 promoter, while those of Bombyx mori Kr-h1(BmKr-h1), Acyrthosiphon pisum Kr-h1(ApKr-h1), Drosophila melanogester Kr-h1(DmKr-h1), Nasonia vitripennis Kr-h1(NvKr-h1), and Nilaparvata lugens Kr-h1(NlKr-h1) are not. JH also interacts with the hormone ecdysone (Ecd), and research from D. melanogaster, B. mori, and T. castaneum suggests that Kr-h1 is a key factor in the JH-Ecd interaction. JH mimics methoprene treatment, which increases the expression of Kr-h1 while reducing that of Broad (B), a transcription factor located downstream of Ecd and its receptor that plays an important role in the ecdysone signaling pathway. This indicates that Br expression might be inhibited by Kr-h1. Although much progress has been made in understanding insect hormone signaling pathways, several key questions still remain. For example, what is the role of Kr-h1 in linking the JH and Ecd signaling pathways? How many other genes form a close connection in the JH signaling cascade? This review highlights the characteristics and functions of Kr-h1 that have been elucidated during the past decade. It also summarizes our understanding of the molecular mechanism of JH, establishes a theoretical basis for the development of biological pesticide, and contributes theoretically to the maintenance of a good ecological environment. 参考文献 相似文献 引证文献