Fig. 1

Identification of an active enhancer with lung cell specificity in the high LD region of rs753955. a Overview of the epigenetic profiling of H3K4me1, H3K4me3, and H3K27ac chromatin modifications, distributions of DNase I hypersensitivity clusters and transcription factor binding sites in the LD region for the human lung fibroblast cell line NHLF released by UCSC databases. The red rectangle is indicative of the putative active enhancer. The locations of the tag SNP and the three highly linked SNPs within the putative enhancer are indicated by vertical dotted lines in red. b A diagram displaying the relative positions of the putative enhancer13q-Enh and two nearest genes, TNFRSF19 and MIPEP, and the Tag-SNP rs753955 marked in a red triangle. c Activity and specificity examination of the putative enhancer 13q-Enh. Different cell lines were transiently transfected with the 13q-Enh-pGL3-promoter plasmid and tested for luciferase activity after 24 h. The pGL3-promoter plasmid without the putative enhancer sequence was used as a negative control. The luciferase signal was normalized to the Renilla signal. (n = 3 per group; error bars are SD; **p < 0.01, *p < 0.05, unpaired Student’s t test). The 13q-Enh displayed significantly high enhancer activity in the normal lung cell lines, Beas-2B, HFL1, and MRC5. d The profiling of H3K27ac chromatin modifications of the 13q-Enh region in a lung tissue and 11 non-lung tissues, indicating the high lung tissue specificity of the 13q-Enh activity. The 13q-Enh enhancer region is marked by a red rectangle