Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500 046, India.
J Biosci. 2021;46.
The midgut of lepidopteran larvae is a multifunctional tissue that performs roles in digestion, absorption, immunity, transmission of pathogens and interaction with ingested various molecules. The proteins localized at the inner apical brush border membrane are primarily digestive proteases, but some of them, like aminopeptidase N, alkaline phosphatase, cadherins, ABC transporter C2, etc., interact with Crystal (Cry) toxins produced by (). In the present study, aminopeptidase N (APN) was characterized as Cry-toxin-interacting protein in the larval midgut of castor semilooper, . Transcriptomic and proteomic analyses revealed the presence of multiple isoforms of APNs (APN1, 2, 4, 6 and 9) which have less than 40% sequence similarity but show the presence of characteristic 'GAMENEG' and zinc-binding motifs. Feeding a sublethal dose of Cry toxin caused differential expression of various APN isoform. Further, 6thgeneration Cry-toxin-exposed larvae showed reduced expression of APN2. This report suggests that larvae exploit altered expression of APNs to overcome the deleterious effects of Cry toxicity, which might facilitate toxin tolerance in the long run.
鳞翅目幼虫的中肠是一种多功能组织，在消化、吸收、免疫、病原体传播以及与摄入的各种分子相互作用方面发挥作用。定位于内顶刷状边界膜的蛋白质主要是消化蛋白酶，但其中一些，如氨肽酶 N、碱性磷酸酶、钙粘蛋白、ABC 转运体 C2 等，与 ()产生的 Crystal (Cry) 毒素相互作用。在本研究中，在蓖麻尺蠖幼虫的中肠中，将氨肽酶 N (APN) 鉴定为 Cry-毒素相互作用蛋白。转录组和蛋白质组分析显示存在多种 APN 同工型 (APN1、2、4、6 和 9)，它们的序列相似度小于 40%，但具有特征性的“GAMENEG”和锌结合基序。喂食亚致死剂量的 Cry 毒素会导致各种 APN 同工型的差异表达。此外，第 6 代 Cry 毒素暴露的幼虫显示 APN2 的表达减少。本报告表明， 幼虫利用 APNs 的改变表达来克服 Cry 毒性的有害影响，这可能从长远来看有助于毒素耐受。
