Noduler, a novel immune up-regulated protein mediates nodulation response in insects
Noduler, a novel immune up-regulated protein mediates nodulation response in insects
复制标题
DOI：
10.4049/jimmunol.179.10.6943
复制
发表时间：
2007-11-15
影响因子：
4.4
通讯作者：
Nagaraju, Javaregowda
中科院分区：
文献类型：
--
作者：
Gandhe, Archana S.;John, Serene H.;Nagaraju, Javaregowda
昆虫的免疫系统包括细胞防御和细胞防御。结瘤是昆虫对微生物感染的主要细胞反应之一，但人们对其了解甚少。通过筛选印度蚕蛾Antheraea mylitta的新免疫基因，我们发现了一种在细菌攻击后几分钟内在血淋巴中上调的蛋白。我们在这里首次证明了这种新蛋白参与介导对细菌的结瘤反应，因此将其命名为Noduler。结节蛋白具有在几种细胞外基质脊椎动物蛋白中发现的特征性卷曲结构域。结核已被证明能在体外结合多种细菌、酵母和昆虫血细胞。此外，结核特异性结合了微生物细胞壁的LPS、脂壁酸和β - 1,3葡聚糖成分。rna干扰介导的敲除结节导致结节数量显著减少，从而增加了幼虫血淋巴中的细菌负荷。结果表明，Noduler是广泛保守的，并通过形成血细胞结节和细菌复合物参与昆虫的早期细菌清除。这一结果将促进对昆虫结瘤机制的进一步研究，并为研究功能尚不清楚的类似哺乳动物蛋白提供线索。
Insect immune system comprises of both Immoral and cellular defenses. Nodulation is one of the major, yet very poorly understood cellular responses against microbial infections in insects. Through screening for novel immune genes from an Indian saturniid silkmoth Antheraea mylitta, we identified a protein up-regulated in hemolymph within minutes upon bacterial challenge. We have shown here, for first time, the involvement of this novel protein in mediating nodulation response against bacteria and hence designated it as Noduler. Noduler possessed a characteristic reeler domain found in several extracellular matrix vertebrate proteins. Noduler was shown in vitro to bind a wide range of bacteria, yeast, and also insect hemocytes. Furthermore, Noduler specifically bound LPS, lipotechoic acid, and beta-1, 3 glucan components of microbial cell walls. RNA-interference mediated knock-down of the Noduler resulted in significant reduction in the number of nodules and consequent increase in bacterial load in larval hemolymph. The results suggest that the Noduler is widely conserved and is involved in very early clearance of bacteria by forming nodules of hemocytes and bacterial complexes in insects. The results would promote further studies for understanding of the crucial but hitherto overlooked nodulation mechanism in insects and also provide cues for the study of similar mammalian proteins whose function is not understood.