CHROMATIN COMPLEXES REGULATING GENE-EXPRESSION IN DROSOPHILA

Polycomb-group proteins form chromatin complexes at target genes such as Ubx, providing a cellular memory of gene activity in early developm ent and determining the later activity of the gene. The complexes, who se constituents vary depending on site and genomic context, initiate a t specific sites, but can extend to involve larger chromatin domains. How they persist through cell proliferation and how they silence gene activity are still open issues.