Primer extension analysis confirms miRNA expression. Total RNA was isolated from A) C7/10 cells or C7/10-WNV312 cells persistently infected with WNV replicons and B, C) Cx. quinquefasciatus mosquitoes fed a non-infectious blood meal (Culex) or a blood meal containing WNV-NY99 (Culex- WNV). 10 μg (A, C) or 4 μg (B) of RNA was used for primer extension to detect miRNAs. For each miRNA, free probe with no RNA is shown as a negative control. Ethidum bromide stained rRNA is shown as loading control.