Fig. 5. Distinct cis-regulatory elements are required for dap expression in epidermis and nervous system. Embryos with either the transgenes dap-1gm (A,C,E) or dap-4gm (B,D,F), which drive expression of p27DAP fused to six Myc epitope tags at the C terminus, were labeled with a DNA stain (A,B) and anti-Myc (C-F) at stage 11 (A-D) or stage 13 (E,F). High-magnification views of the epidermis are shown. (A,B) The DNA staining of the regions shown in C,D, respectively. While dap-1gm is expressed in all epidermal cells during G2 of the final division cycle (C) like the endogenous dap locus (de Nooij et al., 1996; Lane et al., 1996), dap-4gm fails to drive epidermal expression (D). However, dap-4gm is expressed in the peripheral nervous system (F) in a subset of the cells that express dap-1gm (E). Wild-type embryos (G) and homozygous dap⁹ embryos (H) were labeled with anti-DAP at stage 13. dap expression in the nervous system is almost completely eliminated by the dap⁹ deletion.