UASt sequences regulate expression of the ZIKV\NS1 open reading frame (sequence of the PRVABC-59 strain, GB:KX377337, codon optimized for Drosophila), tagged at the C-terminal end with three copies of the Tag:HA epitope. A V188A amino acid replacement (a variant found in a Cambodian strain that is less pathogenic) has been introduced into the ZIKV\NS1 sequence. The ORF is flanked by a pair of incompatible FRT sites (FRT5 and FRT2), which allows for future in vivo exchange of either the promoter or tag sequence.