Analysis of Sex combs reduced HOX gene cis-regulatory elements. Monica T. Cooper, James A. Kennison. Program on Genomics of Differentiation, NIH, Bethesda, MD.

   The Drosophila Hox gene, Sex combs reduced (Scr), is required for patterning the first thoracic segment. The Scr transcription unit spans 35 kb, with at least 35 kb of upstream cis-regulatory sequences. We are testing Scr genomic fragments to identify Polycomb Group response elements (PREs). We are also making targeted knock-out deletions of the PREs in the endogenous gene.