Transgenic construct used in an enhancer blocking assay to characterize and investigate the SF-1 insulator. Encodes two divergently transcribed reporters, a w+mC minigene and lacZ driven by an eve promoter (-42 to +200). The rho neuroectoderm enhancer (NEE), a 2.3kb SF-1 insulator fragment in reverse orientation and the h stripe 1 enhancer (H1) have been inserted in between the two divergent promoters, such that the H1 enhancer is proximal to the eve-lacZ reporter.