Regulation of engrailed and invected expression in the Drosophila central nervous system Video Walkthrough

To study engrailed regulation in a transgenic context, we used a 79kb transgene containing an HA-tagged engrailed gene and its regulatory DNA. We deleted specific fragments that were found to bind a Polycomb Group protein, Polyhomeotic. We collected embryos, fluorescently stained them, and imaged early and late stage embryos. We found misexpression only in late stage embryos in all HA lines, with two lines having the most misexpression. This misexpression was also concentrated in the midline of these two lines. We reasoned that this fragment could be a CNS-specific PRE.