Genetic polymorphisms in the multidrug resistance-associated protein 3 (ABCC3, MRP3) gene and relationship to its mRNA and protein expression in human liver

Pharmacogenetics. 2004 Mar;14(3):155-64. doi: 10.1097/00008571-200403000-00003.

Abstract

Aims: To determine the genetic variability of multidrug resistance protein 3 (MRP3).

Methods: Genomic DNA samples from 103 Caucasians were systematically screened for genetic variations to find a potential relationship with hepatic MRP3 expression. Sequencing comprised all 31 exons, approximately 100 bp of the flanking intronic regions and 2 kb of the 5' UTR.

Results: In total, 51 mutations were identified. Fifteen SNPs were located in the coding exons of MRP3, six of which are nonsynonymous mutations. SNPs 39G>C (allele frequency: 0.5%, located in exon 1), 202C>T (1.6%, exon 2), 1037C>T (0.5%, exon 9), 1537C>A (0.5%, exon 12), 3890G>A (5.2%, exon 27) and 4267G>A (0.6%, exon 29) resulted in Lys13Asn, His68Tyr, Ser346Phe, Gln513Lys, Arg1297His and Gly1423Arg amino acid substitutions, respectively. A splice site mutation (1339-1G>T) was found at the intron 10-exon 11 boundary. To evaluate, whether mutations in the MRP3 gene correlate with human hepatic MRP3 expression, we analyzed the genetic variants in Caucasian liver samples, whose MRP3 mRNA (n = 84) and protein (n = 50) expression has been determined by real time quantitative PCR and Western Blot, respectively. We found a significant correlation of a polymorphism in the 5' promoter region (-211C>T) of MRP3 with mRNA expression. Individuals homozygous and heterozygous for the -211C>T promoter polymorphism had significantly lower MRP3 transcript levels compared to wild-type individuals (P < 0.05). Accordingly, electrophoretic mobility shift assay demonstrated that -211C>T polymorphism affected the binding of nuclear factors.

Conclusions: Multiple genetic polymorphisms of MRP3 exist in Caucasians. The -211C>T promoter polymorphism appears to be associated with altered hepatic MRP3 mRNA expression.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Substitution
  • Blotting, Western
  • Drug Resistance, Multiple
  • Electrophoretic Mobility Shift Assay
  • Exons
  • Gene Frequency
  • Heterozygote
  • Homozygote
  • Humans
  • Liver / metabolism
  • Liver / pathology
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / metabolism*
  • Liver Neoplasms / secondary
  • Multidrug Resistance-Associated Proteins / genetics*
  • Multidrug Resistance-Associated Proteins / metabolism*
  • Mutation*
  • Nuclear Proteins / metabolism
  • Polymerase Chain Reaction
  • Polymorphism, Single Nucleotide*
  • Promoter Regions, Genetic
  • Whites

Substances

  • Multidrug Resistance-Associated Proteins
  • Nuclear Proteins
  • multidrug resistance-associated protein 3