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. 2003 Apr 16;100(9):5223–5228. doi: 10.1073/pnas.0830190100

Figure 1.

Figure 1

Enhancer-blocking activity of suHw paired with heterologous insulators. Expression of the eve-lacZ fusion gene in blastoderm-stage transgenic embryos is visualized by whole-mount in situ hybridization (see Materials and Methods). Embryos are shown anterior to the left and dorsal up. Each transgene is diagrammed underneath the embryos. (A) LacZ reporter expression in a PL3 transgenic embryo showing comparable level of expression is directed by the distal PE and proximal E3 enhancers. (B) LacZ expression in PS3 transgenic embryos showing a reduction in the expression directed by the PE enhancer relative to that directed by E3, indicating insulator activity. (C) LacZ expression in PSS3 embryos. The intense ventral stain directed by PE indicates a loss of insulator activity. (D, F, and H) The lacZ expression in transgenic embryos containing single insulators between the PE and E3 enhancers showing reduction of in the PE-directed expression to different extents: PC3 (D), PB3 (F), and PF3 (H). (E, G, and I) Transgenic embryos containing double insulators between the PE and E3 enhancers: PSC3 (E), PSB3 (G), and PSF3 (I). Little or no PE-directed lacZ expression is seen in the ventral region of these embryos.