Identification of juvenile hormone target genes in the adult female mosquitoes

Many aspects of reproductive maturation in newly emerged adult female mosquitoes are controlled by juvenile hormone (JH). However, the molecular basis of this hormonal regulation remains poorly understood. In this study, we analyzed transcriptome changes in young female adults after topical application of exogenous JH. mRNA levels of 16 and 72 genes were enhanced at 3 h and 12 h after hormone administration, respectively. The observed upregulations can be also induced by the JH analogues, methoprene and pyriproxyfen, but not by farnesol, indicating that these responses are JH-specific. Among the genes activated by JH is the mosquito Krüppel homolog 1 (Kr-h1) gene. Studies in the beetle Tribolium castaneum have indicated that Kr-h1 is transcriptionally activated by JH during metamorphosis and encodes a gene expression regulator acting downstream of the methoprene-tolerant (Met) gene in the JH signaling pathway. We found that the upregulation of AaKr-h1 after eclosion relied on the function of the mosquito Met protein, suggesting that a conserved JH signaling pathway is utilized both in the metamorphosis of T. castaneum and in the adult reproductive maturation of the Aedes aegypti mosquito. This study lays a foundation for a better understanding of the mechanisms of juvenile hormone action.