UASt regulatory sequences are fused upstream of an inverted repeat of a 607bp apolpp fragment (corresponds to a 607bp sequence ending 47bp from the stop codon, which encodes part of the ApoLI protein produced by cleavage of the pro-Apolipophorin precursor). A FRT>HcRed1>FRT cassette separates the two repeats. A transcription termination signal present downstream of HcRed1 within the FRT cassette prevents transcription of the second copy of the repeat, preventing the formation of dsRNA.