CNRS Unit of Evolutionary Genomics, Modeling, and Health (UMR2000), Institut Pasteur, Paris, France.
CNRS Unit of Evolutionary Genomics, Modeling, and Health (UMR2000), Institut Pasteur, Paris, France.
Insect Biochem Mol Biol. 2020 May;120:103339. doi: 10.1016/j.ibmb.2020.103339. Epub 2020 Feb 24.
Hemocytes, the immune cells in mosquitoes, participate in immune defenses against pathogens including malaria parasites. Mosquito hemocytes can also be infected by arthropod-borne viruses but the pro- or anti-viral nature of this interaction is unknown. Although there has been progress on hemocyte characterization during pathogen infection in mosquitoes, the specific contribution of hemocytes to immune responses and the hemocyte-specific functions of immune genes and pathways remain unresolved due to the lack of genetic tools to manipulate gene expression in these cells specifically. Here, we used the Gal4-UAS system to characterize the activity of the Drosophila hemocyte-specific hemolectin promoter in the adults of Anopheles gambiae, the malaria mosquito. We established an hml-Gal4 driver line that we further crossed to a fluorescent UAS responder line, and examined the expression pattern in the adult progeny driven by the hml promoter. We show that the hml regulatory region drives hemocyte-specific transgene expression in a subset of hemocytes, and that transgene expression is triggered after a blood meal. The hml promoter drives transgene expression in differentiating prohemocytes as well as in differentiated granulocytes. Analysis of different immune markers in hemocytes in which the hml promoter drives transgene expression revealed that this regulatory region could be used to study phagocytosis as well as melanization. Finally, the hml promoter drives transgene expression in hemocytes in which o'nyong-nyong virus replicates. Altogether, the Drosophila hml promoter constitutes a good tool to drive transgene expression in hemocyte only and to analyze the function of these cells and the genes they express during pathogen infection in Anopheles gambiae.
血细胞是蚊子中的免疫细胞，参与针对病原体（包括疟疾寄生虫）的免疫防御。蚊子血细胞也可能被节肢动物传播的病毒感染，但这种相互作用的抗病毒或促病毒性质尚不清楚。尽管在蚊子感染病原体期间对血细胞特性的研究已经取得了进展，但由于缺乏专门用于操纵这些细胞中基因表达的遗传工具，血细胞对免疫反应的具体贡献以及免疫基因和途径的血细胞特异性功能仍未得到解决。在这里，我们使用 Gal4-UAS 系统来描述在疟蚊 Anopheles gambiae 成蚊中果蝇血细胞特异性血凝集素启动子的活性。我们建立了一个 hml-Gal4 驱动系，进一步与荧光 UAS 响应系杂交，并检查了 hml 启动子驱动的成虫后代中的表达模式。我们表明，hml 调控区在一组血细胞中驱动血凝集素基因的特异性转基因表达，并且在饱食血液后触发转基因表达。hml 启动子驱动分化前体血细胞和分化的粒细胞中的转基因表达。对 hml 启动子驱动转基因表达的血细胞中的不同免疫标志物进行分析表明，该调控区可用于研究吞噬作用和黑化作用。最后，hml 启动子驱动在复制 o'nyong-nyong 病毒的血细胞中转基因表达。总之，果蝇 hml 启动子是一种在仅血细胞中驱动转基因表达并分析这些细胞及其在疟蚊 Anopheles gambiae 感染病原体过程中表达的基因的功能的良好工具。
