UAS regulatory sequences drive expression of two copies of a 1.4kb genomic fragment spanning exons 2-4 of w which are arranged in an inverted repeat with a 200bp nonpalindromic spacer (derived from Ecol\lacZ) between the two copies of w sequence.
Eye colour: expression of wsp.dsRNA.Scer\UAS under the control of Scer\GAL4Act5C.PI in w+/w- heterozygous females results in an appreciable reduction in eye pigmentation. The red pigment content is about 2% that of control flies.