| Summary: | 博士 === 國防醫學院 === 生命科學研究所 === 92 === Two mosquito STATs, AaSTAT and CtSTAT, have been cloned from Aedes albopictus and Culex tritaeniorhynchus mosquitoes, respectively. These two STATs are more similar to those of Drosophila, Anopheles, and mammalian STAT5 in the DNA binding and SH2 domains. The mRNA transcripts are expressed at all developmental stages, and the proteins are present prominently at the pupal and adult stages in both mosquitoes. Stimulation with LPS resulted in the increase of tyrosine phosphorylation and DNA binding activity and nuclear translocations in fat body cells of AaSTAT and CtSTAT as well as the increase of luciferase activity of a reporter gene containing Drosophila STAT binding motif in mosquito C6/36 cells. After infected with Japanese encephalitis virus, nuclear extracts of C6/36 cells revealed the decrease of tyrosine phosphorylation and DNA binding activity of AaSTAT that could be restored by sodium orthovanadate treatment. Furthermore, sodium orthovanadate treatment could decrease the synthesis of viral protein in C6/36 cells. Taken all the data together, this is the first report to clone and characterize two mosquito STATs with 81% identity and to demonstrate different response of tyrosine phosphorylation and DNA binding of these two STATs by LPS treatment and by JEV infection. This study also provided clues to understanding the possible pathogenesis of JEV, and another approaches to development new vaccines and drugs for flaviviruses.
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