The 1.4kb Tl enhancer (which drives expression in several but not mesodermal tissues) is fused upstream of a minimal Hsp70 promoter driving a 3.5kb Tl cDNA fragment (which includes the entire open reading frame).
wild-type
Tl1.4 rescues Df(3R)Tl-X/+
The muscle defects seen in Df(3R)Tl-X/+ larvae are rescued by Tl1.4.