Fig 8. Insertion of polyA-addition signals weakly attenuates read-through transcription from a P-element promoter and correspondingly reduces repression of the eve promoter.

eve-lacZ and flanking P-element promoter-driven RNA expression in stage 5 embryos from eve pseudo-loci, inserted at the same MiMIC site as in Fig 4, but in the opposite orientation. All loci have homie replaced with phage λ DNA (refer to maps). Positions and orientations of the RNA probes used are shown as black and red arrows in the maps. Images are labeled with black lettering corresponding to black arrows, or red lettering corresponding to the red arrow. The loci in A (PΔ, also used in Fig 4B) and B (PpA2Δ), differ only in the insertion of a tandem array of polyA-addition signals, one from α-tubulin and two from SV40, at the position shown in the map in B.