Cuticle sclerotization in pharate adult and imago of Drosophila melanogaster

Homeotic genes are important for early development, but they are subjected to silencing during the later stages. It is known that Polycomb group proteins are involved in this type of distant regulation. The cut locus, a hierarchal regulator of external sensory organs, spans about 220 kb in 7B region on X chromosome. It is important for the normal development at different stages of Drosophila development from embryo to imago. It follows that the chromatin organization and the regulation of the transcription inside the locus are very complex. Up-to-date silencer elements were not identified in the locus. In the present study we detected a functional silencer in the distal part of the locus. The silencer is located inside the locus control region (LCR), has long protein binding region, and possesses sequences characteristic for PRE/TRE.