What genes are targeted by miRNAs in the antennae of Aedes aegypti?

Host preference likely involves the regulation of hundreds of genes. Mosquitoes, such as the yellow fever mosquito Aedes aegypti, display substantial behavioral changes after acquiring a blood meal. Four-day-old females actively seek humans, but upon blood feeding, this behavior is suppressed. Approximately two days after taking a blood meal, females seek oviposition sites. It was previously unknown how the mRNA and small RNAs transcript levels change upon switching between these behavioral states. We studied how miRNAs might regulate gene expression after blood feeding using RNA-seq. Four-day-old A. aegypti females were artificially blood fed with rabbit blood and the antennae or head and thorax were collected 3, 24, 48 and 72 hours after feeding. Total RNA was extract from samples and small RNA and mRNA libraries were prepared for sequencing. There were modest changes in the transcription of olfaction related genes. However, hundreds of genes are up or down-regulated after feeding (>2folds). Most of the 124 known miRNA in A. aegypti are expressed in female antennae. We also identified over 30 potential new miRNAs. We used the 3’UTR of genes differentially expressed for miRNA target prediction. Relatively few targets were found for the known miRNAs. However, the newly discovered miRNAs have multiple predicted potential targets and thus might play important roles in regulating host/oviposition site seeking behavior. The genetic mechanism of host preference and adaptation might therefore involve not only known protein coding genes, but also miRNAs.