UAS regulatory sequences drive expression of chb.
Scer\GAL4elav.PLu/chbUAS.cLa rescues chb4
The ectopic crossing of the midline by central nervous system axons that is seen in chb4/chb4 embryos is rescued by expression of chbScer\UAS.cLa under the control of Scer\GAL4elav.PLu.