Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, 12159, USA.
Bioinformatics Core, Wadsworth Center, New York State Department of Health, Center for Medical Science, Albany, NY, 12208, USA.
BMC Genomics. 2021 May 27;22(1):396. doi: 10.1186/s12864-021-07551-z.
Transmission of pathogens by vector mosquitoes is intrinsically linked with mosquito's reproductive strategy because anautogenous mosquitoes require vertebrate blood to develop a batch of eggs. Each cycle of egg maturation is tightly linked with the intake of a fresh blood meal for most species. Mosquitoes that acquire pathogens during the first blood feeding can transmit the pathogens to susceptible hosts during subsequent blood feeding and also vertically to the next generation via infected eggs. Large-scale gene-expression changes occur following each blood meal in various tissues, including ovaries. Here we analyzed mosquito ovary transcriptome following a blood meal at three different time points to investigate blood-meal induced changes in gene expression in mosquito ovaries.
We collected ovaries from Aedes aegypti that received a sugar meal or a blood meal on days 3, 10 and 20 post blood meal for transcriptome analysis. Over 4000 genes responded differentially following ingestion of a blood meal on day 3, and 660 and 780 genes on days 10 and 20, respectively. Proteins encoded by differentially expressed genes (DEGs) on day 3 include odorant binding proteins (OBPs), defense-specific proteins, and cytochrome P450 detoxification enzymes. In addition, we identified 580 long non-coding RNAs that are differentially expressed at three time points. Gene ontology analysis indicated that genes involved in peptidase activity, oxidoreductase activity, extracellular space, and hydrolase activity, among others were enriched on day 3. Although most of the DEGs returned to the nonsignificant level compared to the sugar-fed mosquito ovaries following oviposition on days 10 and 20, there remained differences in the gene expression pattern in sugar-fed and blood-fed mosquitoes.
Enrichment of OBPs following blood meal ingestion suggests that these genes may have other functions besides being part of the olfactory system. The enrichment of immune-specific genes and cytochrome P450 genes indicates that ovaries become well prepared to protect their germ line from any pathogens that may accompany the blood meal or from environmental contamination during oviposition, and to deal with the detrimental effects of toxic metabolites.
病媒蚊传播病原体与蚊子的生殖策略密切相关，因为自育型蚊子需要脊椎动物的血液来发育一批卵子。大多数物种的卵子成熟周期都与摄入新鲜血餐紧密相关。在第一次吸血时获得病原体的蚊子可以在随后的吸血中向易感宿主传播病原体，也可以通过受感染的卵子垂直传播给下一代。在每次吸血后，包括卵巢在内的各种组织都会发生大规模的基因表达变化。在这里，我们在三个不同时间点分析了埃及伊蚊卵巢的转录组，以研究蚊子卵巢中基因表达在吸血后的变化。
我们收集了在吸血后第 3、10 和 20 天接受糖水或血餐的埃及伊蚊的卵巢进行转录组分析。在第 3 天摄入血餐后，有超过 4000 个基因表现出差异表达，而在第 10 天和第 20 天分别有 660 个和 780 个基因表现出差异表达。第 3 天差异表达基因（DEGs）编码的蛋白质包括气味结合蛋白（OBPs）、防御特异性蛋白和细胞色素 P450 解毒酶。此外，我们还鉴定了在三个时间点差异表达的 580 个长非编码 RNA。GO 分析表明，第 3 天参与肽酶活性、氧化还原酶活性、细胞外空间和水解酶活性等的基因富集。尽管与第 10 天和第 20 天产卵的糖水喂养的蚊子卵巢相比，大多数 DEGs 与糖水喂养的蚊子卵巢相比已恢复到无显著水平，但在糖喂养和血喂养的蚊子中，基因表达模式仍存在差异。
吸血后 OBP 的富集表明这些基因可能除了作为嗅觉系统的一部分外还有其他功能。免疫特异性基因和细胞色素 P450 基因的富集表明，卵巢已经做好充分准备，以保护其生殖系免受任何可能伴随血餐的病原体或在产卵过程中受到环境污染物的侵害，并应对有毒代谢物的有害影响。
