Fig. 2

Epigenetic landscape of CHRNA4 in human. a Epigenetic landscape and transcription signal around CHRNA4 in human liver, hippocampus, and CD34 hematopoietic stem cells. The RefSeq promoter of CHRNA4 (P1, pink-shaded) shows enrichment of H3K4me3 and H3K27ac histone modifications, especially in human hippocampus. CAGE-seq signal of fetal brain indicates that CHRNA4 was transcribed from RefSeq canonical promoter P1. Liver-specific promoter P2 (blue-shade), which is located ~3.9 KB upstream of the RefSeq promoter, is enriched for strong, active histone modifications. The CAGE-seq signal of adult liver indicates CHRNA4 is transcribed from the liver-specific promoter P2. b Averaged DNA methylation levels of promoters P1 and P2 in human liver, hippocampus, and CD34 hematopoietic stem cells. Mann-Whitney U test was performed to detect statistical significance. c Relative expression level of CHRNA4 measured by qRT-PCR in human GM12878 cell line, brain, and liver. Student t-test was performed to detect statistical significance