13 copies of the lexAop site are fused upstream of the C3PA-GFP photoactivatable fluorescent protein. 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 C3PA-GFP sequences. The 3' UTR (666bp) from the Autographa californica nucleopolyhedrovirus (AcNPV) p10 gene is present downstream of the C3PA-GFP sequences.