Figure 3.

Nucleosome free (or depleted) regions of the CFTR promoter contain potential regulatory elements. (A) The nucleosome occupancy profile of the CFTR-expressing bronchial epithelial cell line 16HBE14o-. Highlighted are the nucleosome-free regions (NFRs 1–4) that fall between or flank the ∼3 relatively well-positioned nucleosomes that lie immediately 5′ of the 'core' CFTR promoter that contains the major transcriptional start sites. The x-axis is numbered as in Figure 1. (B) The predicted nucleosome occupancy (based solely on DNA sequence) of the CFTR promoter region derived by using the in silico model proposed in ref. 44 (C) The assayed region of the CFTR promoter aligned with the PhastCons mammalian species conservation track from the ENCODE Consortium (http://genome.ucsc.edu/ENCODE). Higher peaks represent increased sequence conservation among 28 mammalian genome alignments.