The osk promoter drives expression of GFP and a short 3'UTR with a polyadenylation signal. A fragment corresponding to subdomains IV/V of the bcd 3'UTR has been inserted within a cloning site in the 3'UTR sequence. The bcd sequences contain a 10 nucleotide substitution replacing nucleotides 4449-4458 (coordinates according to accession number X51741) with a synthetic sequence.