A 440bp fragment from an Hsp70 gene from the Hsp70A locus (extends from -400 to +40 relative to the transcription start site) is fused upstream of a myosin intron, a synthetic translation enhancer, GFP and the P10 transcriptional terminator. The Hsp70A sequence includes a heat-shock inducible enhancer, promoter and short 5'UTR; the short 5'UTR is designed to render the reporter insensitive to ovarian Hsp70-directed piRNAs.