Hu Zhi-Gang, Chen Ke-Ping, Yao Qin, Gao Gui-Tian, Xu Jia-Ping, Chen Hui-Qing
Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China.
Yi Chuan Xue Bao. 2006 Nov;33(11):975-83. doi: 10.1016/S0379-4172(06)60132-7.
The ENF peptide family, so termed after the consensus sequence in their amino termini (Glu-Asn-Phe-), is assumed to play multiple important roles in defense reactions, growth regulation, and homeostasis of Lepidopteran insects. The paralytic peptide of Bombyx mori (BmPP) is one such peptide that is involved in the paralytic and plasmatocyte-spreading activities in the hemocyte immune reaction. The growth-blocking peptide of Pseudaletia separata (PsGBP), which is also a member of the ENF peptide family, has similar functions that can reportedly be attenuated by the growth-blocking peptide-binding protein (GBP-BP). Using the fluorescent differential display (FDD) technique, the differential expression pattern of genes in highly susceptible silkworm strain 306 were analyzed, following infection with B. mori nuclear polyhedrosis virus (BmNPV), and a differential band (G12(782)) was obtained from the hemolymph RNA pools. Using 5'-RACE with a specially designed primer based on the FDD study, a 1,401 bp cDNA clone was obtained containing a 1,311 bp open reading frame (ORF, GenBank accession number DQ306881). The deduced protein was highly homologous in primary structure to GBP-BP and was termed B. mori paralytic peptide-binding protein (PP-BP). The B. mori PP-BP gene is organized into two exons and only one intron, using bioinformatics searches.Using RT-PCR analysis, it was found that the B. mori PP-BP gene was expressed almost exclusively in the hemolymph. Real-time quantitative PCR analysis indicated that the B. mori PP-BP mRNA level in B. mori strain 306 exposed to BmNPV was much higher than that in B. mori strain without the virus infection. This result implies that the B. mori PP-BP is related to the cellular immune response after BmNPV invades the hemolymph.
ENF肽家族因其氨基末端的共有序列（Glu-Asn-Phe-）而得名，被认为在鳞翅目昆虫的防御反应、生长调节和体内平衡中发挥多种重要作用。家蚕麻痹肽（BmPP）就是这样一种肽，它参与血细胞免疫反应中的麻痹和浆细胞扩散活动。粘虫生长阻滞肽（PsGBP）也是ENF肽家族的成员，具有类似的功能，据报道其功能可被生长阻滞肽结合蛋白（GBP-BP）减弱。利用荧光差异显示（FDD）技术，分析了高感家蚕品系306感染家蚕核型多角体病毒（BmNPV）后基因的差异表达模式，从血淋巴RNA池中获得了一条差异条带（G12(782)）。基于FDD研究，使用专门设计的引物进行5'-RACE，获得了一个1401 bp的cDNA克隆，其中包含一个1311 bp的开放阅读框（ORF，GenBank登录号DQ306881）。推导的蛋白质在一级结构上与GBP-BP高度同源，被命名为家蚕麻痹肽结合蛋白（PP-BP）。通过生物信息学搜索发现，家蚕PP-BP基因由两个外显子和一个内含子组成。通过RT-PCR分析发现，家蚕PP-BP基因几乎只在血淋巴中表达。实时定量PCR分析表明，感染BmNPV的家蚕品系306中家蚕PP-BP mRNA水平远高于未感染病毒的家蚕品系。这一结果表明，家蚕PP-BP与BmNPV侵入血淋巴后的细胞免疫反应有关。
