Molecular biology of mosquito vitellogenesis: from basic studies to genetic engineering of antipathogen immunity
Molecular biology of mosquito vitellogenesis: from basic studies to genetic engineering of antipathogen immunity
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DOI：
10.1016/s0965-1748(02)00090-5
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发表时间：
2002-10-01
影响因子：
3.8
通讯作者：
Attardo, G
中科院分区：
文献类型：
--
作者：
Raikhel, AS;Kokoza, VA;Attardo, G
阐明由血粉激活的基因的阶段和组织特异性表达的分子机制对于当前针对利用分子遗传学开发蚊子和病原体控制的新策略的努力是非常重要的。这些基因的调节区可用于以精确的时间和空间方式在工程化载体中表达抗病原体效应分子，其被设计为最大限度地影响病原体。脂肪体是工程抗病原体特性的特别重要的靶标，因为在昆虫中，它是将其产物释放到血淋巴、环境或大多数病原体的交叉路口的有效分泌组织。最近，我们已经通过工程化埃及伊蚊的稳定复制系提供了这一概念的证据，其中调节区A。埃及卵黄蛋白原（Vg）基因激活高水平的脂肪体特异性表达的一种有效的抗菌因子，防御素，在响应血餐。进一步研究的Vg基因利用果蝇和伊蚊转化确定顺式调节位点负责状态和脂肪体特异性激活该基因通过血餐触发级联。这些分析揭示了Vg基因的2.1 kb上游部分的三个调控区。含有EcR/USP、加塔、C/EBP和HNF 3/fkh的结合位点的近端区域是低水平的正确组织特异性和阶段特异性表达所必需的。中位数区域，携带早期蜕皮激素反应因子E74和E75的位点，负责阶段特异性的激素增强的Vg表达。最后，远端富含GATA的区域是Vg基因特有的极高表达水平所必需的。此外，我们的研究表明，参与控制Vg基因表达的几个转录因子本身就是血餐介导的调节级联反应的靶点，从而大大放大了该级联反应对Vg基因的影响。这项研究为未来设计蚊子特异性表达盒奠定了基础，这些表达盒具有预期的阶段特异性和组织特异性，可达到所需的转基因表达水平。(C)2002爱思唯尔科技有限公司版权所有。
Elucidation of molecular mechanisms underlying stage- and tissue-specific expression of genes activated by a blood meal is of great importance for current efforts directed towards utilizing molecular genetics to develop novel strategies of mosquito and pathogen control. Regulatory regions of such genes can be used to express anti-pathogen effector molecules in engineered vectors in a precise temporal and spatial manner, designed to maximally affect a pathogen. The fat body is a particularly important target for engineering anti-pathogen properties because in insects, it is a potent secretory tissue releasing its products to the hemolymph, an environment or a crossroad for most pathogens. Recently, we have provided proof of this concept by engineering stable transformant lines of Aedes aegypti mosquito, in which the regulatory region A. aegypti vitellogenin (Vg) gene activates high-level fat body-specific expression of a potent anti-bacterial factor, defensin, in response to a blood meal. Further study of the Vg gene utilizing Drosophila and Aedes transformation identified cis-regulatory sites responsible for state- and fat body-specific activation of this gene via a blood-meal-triggered cascade. These analyses revealed three regulatory regions in the 2.1-kb upstream portion of the Vg gene. The proximal region, containing binding sites to EcR/USP, GATA, C/EBP and HNF3/fkh, is required for the correct tissue- and stage-specific expression at a low level. The median region, carrying sites for early ecdysone response factors E74 and E75, is responsible for a stage-specific hormonal enhancement of the Vg expression. Finally, the distal GATA-rich region is necessary for extremely high expression levels characteristic to the Vg gene. Furthermore, our study showed that several transcription factors involved in controlling the Vg gene expression, are themselves targets of the blood meal-mediated regulatory cascade, thus greatly amplifying the effect of this cascade on the Vg gene. This research serves as the foundation for the future design of mosquito-specific expression cassettes with predicted stage- and tissue specificity at the desired levels of transgene expression. (C) 2002 Elsevier Science Ltd. All rights reserved.