Honegger Hans-Willi, Dewey Elizabeth M, Ewer John
Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2008 Dec;194(12):989-1005. doi: 10.1007/s00359-008-0386-3. Epub 2008 Nov 13.
Bursicon was identified in 1965 as a peptide neurohormone that initiates the tanning of the insect cuticle immediately after the shedding of the old one during the final stages of the molting process. Its molecular identity as an approximately 30 kDa bioactive heterodimer consisting of two cystine knot proteins resisted elucidation for 43 years. The sequence of the two bursicon subunits is highly conserved among arthropods, and this conservation extends even to echinoderms. We review the efforts leading to bursicon's characterization, the identification of its leucine-rich repeat-containing, G protein-coupled receptor (LGR2), and the progress towards revealing its various functions. It is now clear that bursicon regulates different aspects of wing inflation in Drosophila melanogaster besides being involved at various points in the cuticle tanning process in different insects. We also describe the current knowledge of the expression of bursicon in the central nervous system of different insects in large homologous neurosecretory cells, and the changes in its expression during the development of Manduca sexta and D. melanogaster. Although much remains to be learned, the elucidation of its molecular identity and that of its receptor has provided the breakthrough needed for investigating the diverse actions of this critical insect neurohormone.
1965年，羽化激素被鉴定为一种肽类神经激素，在蜕皮过程的最后阶段，旧表皮脱落后，它会立即引发昆虫表皮的鞣化。其分子身份是一种由两个胱氨酸结蛋白组成的约30 kDa生物活性异二聚体，这一身份在43年里一直难以阐明。羽化激素的两个亚基序列在节肢动物中高度保守，甚至在棘皮动物中也存在这种保守性。我们回顾了对羽化激素进行表征的研究历程、其富含亮氨酸重复序列的G蛋白偶联受体（LGR2）的鉴定，以及在揭示其各种功能方面所取得的进展。现在已经清楚，羽化激素除了在不同昆虫的表皮鞣化过程中的各个环节发挥作用外，还调节黑腹果蝇翅膀充气的不同方面。我们还描述了目前关于羽化激素在不同昆虫中枢神经系统中在大型同源神经分泌细胞中的表达情况，以及在烟草天蛾和黑腹果蝇发育过程中其表达的变化。尽管仍有许多有待了解的地方，但对其分子身份及其受体的阐明为研究这种关键昆虫神经激素的多种作用提供了所需的突破。
