A 7.6 kb EcoRI fragment from the intron of lab regulates expression of a GAL4 driver. The enhancer fragment is depicted in figure 7 of Chouinard and Kaufman, 1991 (http://flybase.org/reports/FBrf0053767.html).
ScerGAL4lab.DR drives expression in embryos in the dorsal ridge, salivary glands, and in the head; head expression is not observed for endogenous lab expression. The P{lab-GAL4.DR}H1 insertion additionally drives embryonic expression in the frontal sac and in ectodermal stripes.