Fig. 6. The PTE is able to regulate expression of an ectopic promoter. In
the W-5-EZ construct (top diagram), the IAB5 enhancer is located between the
white and even-skipped (eve) promoters. In this
configuration, IAB5 is able to drive expression from white (A)
and eve-lacZ (B). Insertion of the 255 bp PTE sequence
adjacent to the eve-lacZ promoter in the W-5-PTE-EZ construct (bottom
diagram) resulted in strong expression of lacZ (D) and an
absence of expression of white (C), indicating that IAB5 is
now exclusively activating the eve-lacZ promoter.