Development of a Sindbis virus expression system that efficiently expresses green fluorescent protein in midguts of Aedes aegypti following per os infection

A double subgenomic Sindbis (dsSIN) virus, MRE/3′2 J/GFP, was constructed to efficiently express green fluorescent protein (GFP) in the midgut of Aedes aegypti following per os infection. The MRE/3′2 J/GFP RNA genome contained the nonstructural genes and cis‐acting sequences of the dsSIN virus, TE/3′2 J/GFP, but had the structural genes of MRE16 SIN virus. MRE/3′2 J/GFP virus, unlike TE/3′2 J/GFP virus, efficiently infected mosquitoes orally. At 1–2 days postinfection, GFP was observed as multiple foci of expression on the lumenal side of the midgut. At 10–12 days postinfection, thirteen of fifteen mosquitoes infected with MRE/3′2 J/GFP virus had high levels of GFP expression in the mosquito midgut. The MRE3′2 J dsSIN expression system should be an important tool for efficient gene expression in Ae. aegypti midguts.