UASt sequences regulate expression of a chimeric protein in which the putative activation domain of ci has been replaced with the en repression domain (EnR). The protein contains amino acids 1-970 of ci fused to EnR.
wing vein L3, with Scer\GAL471B
wing vein L4, with Scer\GAL471B
Scer\GAL471B induced expression causes fusion between vein L3 and L4.