Functional characterization of genetic variations in the MDR3 promoter

► There were 11 MDR3 promoter variants in 126 Koreans and the one of them was novel. ► Two common promoter haplotypes showed a significantly decreased promoter activity. ► NF-Y is involved in the regulation of transcriptional activity of MDR3. ► Two haplotypes may affect PK/PD of various drugs that are substrates of MDR3.