Division of Natural Resources, Henan Institute of Science and Technology, Xinxiang, Henan, 453007, China.
Division of Plant Sciences, University of Missouri, Columbia, MO, 65201, USA.
Fish Shellfish Immunol. 2020 Apr;99:555-561. doi: 10.1016/j.fsi.2020.02.053. Epub 2020 Feb 25.
Bursicon (burs) is a neuropeptide hormone consisting of two cystine-knot proteins (burs α and burs β), and burs α-β is responsible for cuticle tanning in insects. Further studies show that burs homodimers induce prophylactic immunity. Here, we investigated the hypothesis that burs homodimers act in regulating immunity in the red swamp crayfish Procambarus clarkii. We found that burs α and burs β are expressed in neural system of crayfish. Treating crayfish with recombinant burs-homodimer proteins led to up-regulation of several anti-microbial peptide (AMP) genes, and RNAi-mediated knockdown of burs led to decreased expression of AMP genes. The burs proteins also facilitated bacterial clearance and decreased crayfish mortality upon bacterial infection. Furthermore, burs proteins activated the transcriptional factor Relish, and knockdown of Relish abolished the influence of recombinant burs homodimers on AMP induction. We infer the burs homodimers induce expression of AMP genes via Relish in crayfish and this study extends this immune signaling pathway from insects to crustaceans.
保幼激素（burs）是一种由两个半胱氨酸环蛋白（bursα和bursβ）组成的神经肽激素，bursα-β负责昆虫的表皮鞣制。进一步的研究表明，burs 同源二聚体诱导预防性免疫。在这里，我们假设 burs 同源二聚体在调控美洲红螯螯虾 Procambarus clarkii 的免疫中起作用。我们发现 bursα和 bursβ在螯虾的神经系统中表达。用重组burs-同源二聚体蛋白处理螯虾会导致几种抗菌肽（AMP）基因的上调，而 burs 的 RNAi 介导敲低会导致 AMP 基因的表达下调。burs 蛋白还促进了细菌清除，并降低了细菌感染时螯虾的死亡率。此外，burs 蛋白激活了转录因子 Relish，而 Relish 的敲低消除了重组 burs 同源二聚体对 AMP 诱导的影响。我们推断 burs 同源二聚体通过 Relish 在螯虾中诱导 AMP 基因的表达，本研究将这一免疫信号通路从昆虫扩展到甲壳类动物。
