Two copies of the eve mesoderm enhancer (+5.8 to +6.6 kb) lie upstream of the eve promoter (nt -275 to +11), followed by polylinker sequences and the eve 5' untranslated leader (+91 to +9nt). This is fused with the GAL4 coding region (resulting in the replacement of the yeast initiation site being replaced by that from eve), and followed by the eve 3' untranslated region (+1306 to +1521 nt).