Chitosan/siRNA nanoparticle targeting demonstrates a requirement for single-minded during larval and pupal olfactory system development of the vector mosquito Aedes aegypti.
Chitosan/siRNA nanoparticle targeting demonstrates a requirement for single-minded during larval and pupal olfactory system development of the vector mosquito Aedes aegypti.
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DOI：
10.1186/1471-213x-14-9
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发表时间：
2014-02-19
影响因子：
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通讯作者：
Duman-Scheel M
中科院分区：
文献类型：
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作者：
Mysore K;Andrews E;Li P;Duman-Scheel M
基本上对媒介蚊子嗅觉系统发育的遗传调控一无所知，蚊子利用嗅觉线索来检测血粉宿主。对果蝇的研究已经确定了转录因子的调节矩阵，该矩阵控制嗅觉受体神经元（ORN）中蛹/成虫气味受体（OR）基因的表达。然而，目前尚不清楚在黑腹果蝇调节基质中起作用的转录因子是否是蚊子中 OR 表达所必需的。此外，在包括黑腹果蝇在内的任何昆虫中，幼虫嗅觉系统发育过程中 OR 表达的调节远不如蛹/成虫复杂。在这里，我们研究了登革热媒介蚊子埃及伊蚊发育中的幼虫嗅觉系统中 OR 表达的调节。埃及伊蚊具有八种转录因子的直系同源物，可调节黑腹果蝇蛹/成虫中的 OR 表达。这些转录因子在埃及伊蚊幼虫触角感觉神经元中表达，这些转录因子的共有结合位点位于埃及伊蚊 OR 基因的 5' 侧翼区域。 Single-thought (Sim) 的共有结合位点位于超过一半的埃及伊蚊 OR 基因附近，表明该转录因子是蚊子 OR 表达的主要调节因子。为了在功能上测试这一假设，在幼虫嗅觉发育过程中使用壳聚糖/siRNA 纳米颗粒来靶向 sim。这些实验表明，Sim 正向调节 OR 基因的一大子集的表达，包括 orco，异聚 OR/Orco 复合物组装和功能中的专性共受体。在模拟击倒幼虫中还发现触角叶的神经支配减少。这些 OR 表达和触角叶缺陷与幼虫气味跟踪行为缺陷相关。在 sim 敲低蛹中也观察到 OR 表达和触角叶缺陷。 这项研究的结果表明，Sim 在埃及伊蚊幼虫和蛹嗅觉系统发育过程中具有多种功能。
Essentially nothing is known about the genetic regulation of olfactory system development in vector mosquitoes, which use olfactory cues to detect blood meal hosts. Studies in Drosophila melanogaster have identified a regulatory matrix of transcription factors that controls pupal/adult odorant receptor (OR) gene expression in olfactory receptor neurons (ORNs). However, it is unclear if transcription factors that function in the D. melanogaster regulatory matrix are required for OR expression in mosquitoes. Furthermore, the regulation of OR expression during development of the larval olfactory system, which is far less complex than that of pupae/adults, is not well understood in any insect, including D. melanogaster. Here, we examine the regulation of OR expression in the developing larval olfactory system of Aedes aegypti, the dengue vector mosquito. A. aegypti bears orthologs of eight transcription factors that regulate OR expression in D. melanogaster pupae/adults. These transcription factors are expressed in A. aegypti larval antennal sensory neurons, and consensus binding sites for these transcription factors reside in the 5’ flanking regions of A. aegypti OR genes. Consensus binding sites for Single-minded (Sim) are located adjacent to over half the A. aegypti OR genes, suggesting that this transcription factor functions as a major regulator of mosquito OR expression. To functionally test this hypothesis, chitosan/siRNA nanoparticles were used to target sim during larval olfactory development. These experiments demonstrated that Sim positively regulates expression of a large subset of OR genes, including orco, the obligate co-receptor in the assembly and function of heteromeric OR/Orco complexes. Decreased innervation of the antennal lobe was also noted in sim knockdown larvae. These OR expression and antennal lobe defects correlated with a larval odorant tracking behavioral defect. OR expression and antennal lobe defects were also observed in sim knockdown pupae. The results of this investigation indicate that Sim has multiple functions during larval and pupal olfactory system development in A. aegypti.