20 copies of the UAS site are fused upstream of the shi¹ coding region (this encodes a temperature-sensitive dominant negative form of shi) which is tagged at the C-terminal end with GFP. A small intron derived from the Mhc gene followed by a synthetic AT-rich 21bp sequence made by combining the Cavener consensus sequence with elements from the Malacosoma neustria nucleopolyhedrovirus (MnNPV) polyhedrin gene has been inserted between the promoter and coding sequences. The 3' UTR (666bp) from the Autographa californica nucleopolyhedrovirus (AcNPV) p10 gene is present downstream of the coding sequence.