The SNP of rs6854845 suppresses transcription via the DNA looping structure alteration of super-enhancer in colon cells

Single-nucleotide polymorphisms (SNPs) identified by Genome-Wide Association Studies (GWASs) have been determined to closely connect with multiple diseases. Previous studies revealed one underlying mechanism that SNPs located within the regulatory elements could affect the encoding gene expression through long-range regulation. SNP rs6854845 was suggested to be a risk of colon cancer in human population. Nevertheless, the underlying molecular mechanism for colon carcinogenesis remains largely unknown. In present study, rs6854845 with G > T mutation in situ in FHC, HCT-116 and SW-480 cells were generated by Crispr/Cas9. The nearby chromatin organization was investigated by chromatin conformation capture (3C). And the expression of coding gene regulated by super-enhancer (SE) was detected by real-time PCR. We observed a significantly different pattern of the genome organization upon rs6854845 generation in colon epithelial cells but not in colon cancer cells. Moreover, we observed the shifted enrichment of H3K4me1 and H3K27ac at the SE (chr4:75.7M-76.0 M) where rs6854845 located. Furthermore, we observed that the transcription of the gene clusters regulated by SE were affected by rs6854845 in colon cells. Overall, our results demonstrated that SNP rs6854845 located in SE could destroy the long-range chromosomal interaction between SE and target gene clusters thereby affecting the transcription of these genes. (C) 2019 Elsevier Inc. All rights reserved.