Dipartimento di Biologia, Difesa e Biotecnologie Agro-Forestali, Università della Basilicata, Potenza, Italy.
Insect Biochem Mol Biol. 2009 Nov;39(11):801-13. doi: 10.1016/j.ibmb.2009.09.005. Epub 2009 Sep 26.
We report the cloning of a gene and the characterization of the encoded protein, which is released by the teratocytes of the parasitoid Aphidius ervi in the haemocoel of the host aphid Acyrthosiphon pisum. The studied protein was identified by LC-MS/MS, and the gathered information used for isolating the full length cDNA. The corresponding gene was made of 3 exons and 2 introns, and was highly expressed in the adult wasps and in parasitized hosts. The translation product, which was named Ae-ENO, showed a very high level of sequence identity with insect enolases. In vivo immunodetection experiments evidenced Ae-ENO localization in round spots, present in the teratocytes and released in the host haemocoel. Moreover, strong immunoreactivity was detected on the surface of A. ervi larvae and of host embryos. Ae-ENO expressed in insect cells was not secreted in the medium, indicating the occurrence in the teratocytes of an unknown pathway for Ae-ENO release. The recombinant protein produced in bacteria under native conditions was a dimer, with evident enolase activity (K(m) = 0.086 +/- 0.017 mM). Enolase is a well known enzyme in cell metabolism, which, however, is associated with a multifunctional role in disease, when present in the extracellular environment, on the surface of prokaryotic and eukaryotic cells. In these cases, the enolase mediates the activation of enzymes involved in the invasion of tissues by pathogens and tumour cells, and in the evasion of host immune response. The possible role played by Ae-ENO in the host regulation process is discussed in the light of this information.
我们报道了一个基因的克隆及其编码蛋白的特性，该蛋白由寄生蜂蚜茧蜂的滋养细胞在宿主蚜虫豌豆蚜的血腔中释放。通过 LC-MS/MS 鉴定了研究蛋白，并利用收集到的信息分离全长 cDNA。相应的基因由 3 个外显子和 2 个内含子组成，在成虫和寄生宿主中高度表达。翻译产物命名为 Ae-ENO，与昆虫烯醇酶具有非常高的序列同一性。体内免疫检测实验证明 Ae-ENO 定位于滋养细胞中的圆形斑点中，并在宿主血腔中释放。此外，在 A. ervi 幼虫和宿主胚胎的表面检测到强烈的免疫反应。在昆虫细胞中表达的 Ae-ENO 不会分泌到培养基中，这表明 Ae-ENO 的释放途径在滋养细胞中未知。在细菌中以天然条件表达的重组蛋白是二聚体，具有明显的烯醇酶活性（K(m) = 0.086 +/- 0.017 mM）。烯醇酶是细胞代谢中众所周知的酶，但当存在于细胞外环境中、在原核和真核细胞表面时，它与疾病中的多功能作用相关。在这些情况下，烯醇酶介导与病原体和肿瘤细胞侵袭组织以及逃避宿主免疫反应相关的酶的激活。根据这些信息，讨论了 Ae-ENO 在宿主调控过程中可能发挥的作用。
