Fig. 1. Eight kilobases of upstream en regulatory DNA includes sequences with PRE activity. (A) Consensus binding sites for DNA-binding proteins implicated in PRE activity are shown (Brown et al., 2005) along with the location of PSE1 and PSE2. The line below shows the extent of deletion present in the en mutant, en⁵³⁰. (B) DNA constructs used in these experiments. Arrows indicate the start of transcription. Black boxes indicate P element ends. Green boxes indicate en DNA. Red boxes indicate mini-white DNA. Blue boxes indicate lacZ DNA. White boxes indicate DNA deleted from the construct. Sequences deleted from PSE2 extend from -395 to -576 bp upstream of the start of en transcription. Sequences deleted from both extend from -395 bp to -2407 bp. Misexpression (ME) is defined as detection of β-gal protein between the stripes. Number of lines with misexpression/total number of lines stained. Misexpression in P[en1] and P[PSE2] lines was much less extensive than that seen in both (see Fig. 2). (C) En (green) and β-gal protein (red) in a P[en1] line in a wild type and a ph-d⁴⁰¹ ph-p⁶⁰² double mutant embryo. Anterior is leftwards, dorsal is upwards. Ten hours AEL (after egg laying). DL, double label. En is present in a single PNS cell between the stripes, but β-gal is not.