Abstract

EF1A2 binds p85α to activate the PI3K/Akt/TOR pathway in Aedes aegypti. • EF1A2 governs lipid and glycogen mobilization from the fat body. • EF1A2 promotes vitellogenin transcription and oocyte maturation. • EF1A2 links nutrient metabolism to reproductive output in Ae. Aegypti. • EF1A2 function in reproduction is conserved across Aedes and Culex mosquitoes. As a major arbovirus vector, Aedes aegypti relies on high fecundity, which is governed by nutrient metabolism and vitellogenesis via the PI3K/Akt/TOR pathway. However, the upstream regulators linking nutrition to this pathway remain unclear. Here, we found translation elongation factor EF1A2 (AAEL017096) is a key regulator of reproduction. Knockdown via RNAi and CRISPR/Cas9-mediated knockout of EF1A2 led to complete arrest of ovarian development and sharply reduced egg production—a conserved phenotype also observed in Aedes albopictus and Culex quinquefasciatus . Mechanistically, loss of EF1A2 disrupted mobilization of lipid and glycogen reserves from the fat body, causing nutrient retention and suppressed catabolism. Additionally, EF1A2 binds to the PI3K regulatory subunit p85α to promote Akt phosphorylation , thereby activating the PI3K/Akt/TOR pathway and driving vitellogenin (Vg) transcription, essential for oocyte maturation. These findings identify EF1A2 as a novel upstream regulator of the PI3K/Akt/TOR pathway, linking nutrient metabolism to mosquito reproductive output. This study reveals a non-canonical function of an EF1A family member in upstream pathway regulation and provides new insights into how mosquitoes integrate nutritional signals with reproduction, potentially informing future vector control strategies. In wild-type (WT) Ae. Aegypti females, blood meal-derived nutrients trigger EF1A2, which directly binds the PI3K regulatory subunit p85α. This interaction enhances Akt phosphorylation and activates the PI3K/Akt/TOR signaling cascade, driving vitellogenin (Vg) transcript