Association between DNA Methylation in the miR-328 5’-Flanking Region and Inter-individual Differences in miR-328 and BCRP Expression in Human Placenta

摘要: MicroRNA (miRNA) are non-coding small RNA that regulate gene expression. MiR-328 is reported to influence breast cancer resistance protein (BCRP) expression in cells. As a large inter-individual difference BCRP levels observed various human tissues, the contribution of miR-328 these differences interest. We hypothesized DNA methylation promoter region responsible for levels, leading variability placenta. The association between placental and was analyzed, then 5'-flanking regulatory mechanisms causing were examined. significantly correlated with mRNA (Rs = -0.560, P < 0.01) -0.730, levels. It also up-regulated by demethylating agent 5-aza-2’-deoxycytidine BCRP-expressing Luciferase assays differentially methylated reporter constructs indicated 5’-flanking including predicted CpG island remarkably decreased transcriptional activity compared unmethylated constructs. selected CCAAT/enhancer binding α (C/EBPα), located within island, silico analysis. To elucidate role C/EBPα expression, chromatin immunoprecipitation assay, deletion analysis, electrophoretic mobility shift assay (EMSA) performed. C/EBPα-binding site-truncated showed activity, EMSA sites island. Finally, patterns several dinucleotides proximal two negatively positively samples. These results suggest involved