Enhancer activity of HS2 of the human P-LCR is modulated by distance from the key nucleosome

A class of curved DNA appears universally in eukaryotic genomic DNA at an a verage distance of similar to 680 bp and shows nucleosome positioning activ ity by having high affinity for histone core particles in an orientation- a nd position-dependent manner. Here, we report that the enhancer activity at DNase I hypersensitive site 2 (HS2) of the human beta -globin locus contro l region (beta -LCR) can be modulated by the curved DNA located at a distan ce of two nucleosomes from HS2 and that the nucleosome at the curved DNA re gulates nearby nucleosome phases as a key nucleosome. Erythroid-specific nu cleosome phases which caused deviation of the NF-E2 (p18-p45 dimer) binding site from the nucleosome dyad axis were over-represented when the distance between the key nucleosome and HS2 exceeded 80 bp longer than the original length. At this state, enhancer activity was similar to 50% of that in the original construct, presumably due to reduced binding of transcription fac tors.