Influenza A virus (IAV) of the family Orthomyxoviridae is an enveloped, negative-strand RNA virus. The IAV genome is composed of eight different vRNA segments that altogether encode up to 13 proteins [4] [5] [6] [7] . Each vRNA and cRNA possesses untranslated regions (UTRs) of varying length at the 39 and 59 ends. The first 12 and 13 nucleotides at the 39 and 59 UTRs of the vRNAs and cRNAs are highly conserved among different RNA segments. These highly conserved partly complementary UTRs, which form a ''panhandle'' or ''corkscrew'' conformation by alternative modes of base-pairing, constitute the promoter structure for RNA synthesis [8, 9] . The panhandle conformation results from base-pairing between 59 and 39 terminal ends of the viral RNA segment with a small internal loop [10, 11] , while the corkscrew structure consists of a six base-pair RNA rod in the distal element in conjunction with two stem-loop structures of two short-range base-pairs [12] .