A 917 bp genomic fragment containing the upstream regulatory sequences and the 5' UTR of the nos gene are cloned upstream of the Tn10\tetR coding region, including an N-terminal fused nuclear localization signal, and an EGFP tag. An 860 bp genomic fragment containing the 3' UTR and downstream flanking sequences of αTub84B are cloned downstream of the coding sequence. (The nos 5' and αTub84B regions direct maternal expression of transgenes throughout the embryo.)