Suppression in Drosophila: su(Hw) and su(f) gene products interact with a region of gypsy (mdg4) regulating its transcriptional activity.

The gypsy (mdg4) mobile element of Drosophila contains two closely spaced regions which bind proteins from nuclear extracts. One of these is an imperfect palindrome having homology with the lac-operator of Escherichia coli; the other contains a reiterated sequence (5'PyPuT/C TGCATAC/TPyPy) homologous to the octamer that is the core of many enhancers and upstream promoter elements. Transient expression of deletion mutants has shown that these DNA regions are negative and positive regulators of transcription.