Regulatory effects of genomic translocations at the human carboxylesterase-1 (CES1) gene locus.
Pharmacogenet Genomics
; 26(5): 197-207, 2016 May.
Article
em En
| MEDLINE
| ID: mdl-26871237
ABSTRACT
OBJECTIVE:
CES1 encodes carboxylesterase-1, an important drug-metabolizing enzyme with high expression in the liver. Previous studies have reported a genomic translocation of the 5' region from the poorly expressed pseudogene CES1P1, to CES1, yielding the structural variant CES1VAR. The aim of this study was to characterize this translocation and its effect on CES1 expression in the human liver. MATERIALS ANDMETHODS:
Experiments were conducted in human liver tissues and cell culture (HepG2). The promoter and exon 1 of CES1 were sequenced by Sanger and Ion Torrent sequencing to identify gene translocations. The effects of CES1 5'UTRs on mRNA and protein expression were assessed by quantitative real-time PCR, allelic ratio mRNA analysis by primer extension (SNaPshot), quantitative targeted proteomics, and luciferase reporter gene assays.RESULTS:
Sequencing of CES1 identified two translocations first, CES1VAR (17% minor allele frequency) comprising the 5'UTR, exon 1, and part of intron 1. A second shorter translocation, CES1SVAR, was observed excluding exon 1 and intron 1 regions (<0.01% minor allele frequency). CES1VAR is associated with 2.6-fold decreased CES1 mRNA and â¼1.35-fold lower allelic mRNA. Luciferase reporter constructs showed that CES1VAR decreases luciferase activity 1.5-fold, whereas CES1SVAR slightly increases activity. CES1VAR was not associated with CES1 protein expression or metabolism of the CES1 substrates enalapril, clopidogrel, or methylphenidate in the liver.CONCLUSION:
The frequent translocation variant CES1VAR reduces mRNA expression of CES1 in the liver by â¼30%, but protein expression and metabolizing activity in the liver were not detectably altered - possibly because of variable CES1 expression masking small allelic effects. Whether drug therapies are affected by CES1VAR will require further in-vivo studies.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Translocação Genética
/
Hidrolases de Éster Carboxílico
/
Fígado
Tipo de estudo:
Prognostic_studies
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Pharmacogenet Genomics
Assunto da revista:
FARMACOLOGIA
/
GENETICA MEDICA
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Estados Unidos