The Many Roles of Cohesin in Drosophila Gene Transcription

The cohesin protein complex mediates sister chromatid cohesion to ensure accurate chromosome segregation, and also influences gene transcription in higher eukaryotes. Modest deficits in cohesin function that do not alter chromosome segregation cause significant birth defects. The mechanisms by which cohesin participates in gene regulation have been studied in Drosophila, revealing that it is involved in gene activation by transcriptional enhancers and epigenetic gene silencing mediated by Polycomb group proteins. Recent studies reveal that early DNA replication origins are important for determining which genes associate with cohesin, and suggest that cohesin at replication origins is important for establishing both sister chromatid cohesion and enhancer-promoter communication.