Long-range communication between enhancers and promoters regulates gene expression in many developmental situations. In Drosophila wing margin external sensory organs, an enhancer 85 kb upstream of the cuthomeodomain gene activates its expression. Nipped-B, which loads the cohesin complex onto chromosomes, facilitates this activation. On p. 4743, Dorsett and co-workers report that cohesin also regulates cut gene expression. They show that cohesin binds between the wing margin enhancer and the cut promoter in cultured Drosophila cells. Reduced expression of the Smc1 cohesin subunit and a mutation in the cohesin loading factor Pds5 that reduces cohesin binding to chromosomes both increase cut expression. The researchers conclude that cohesin inhibits the long-range activation of cut and suggest that the effects of cohesin on gene expression could underlie the developmental defects seen in Cornelia de Lange syndrome, which is caused by mutations in the human Nipped-B homolog.