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A novel transcription mechanism activated by ethanol: induction of Slc7a11 expression via inhibiting the DNA‐binding activity of repressor OCT1 in mouse hepatic stellate cells
Author(s) -
Lin Xinghua,
Yang Hong,
Zhang Hongfeng,
Zhou LiChun,
Guo ZhongMao
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1151.1
Subject(s) - microbiology and biotechnology , repressor , chromatin immunoprecipitation , promoter , transcription (linguistics) , electrophoretic mobility shift assay , transcription factor , hepatic stellate cell , messenger rna , dna , ethanol , gene expression , chemistry , biology , gene , biochemistry , linguistics , philosophy , endocrinology
The objective of this study is to determine the mechanism underlying ethanol‐induced expression of solute carrier family 7 member 11 (Slc7a11). Quantitative real‐time RT‐PCR assay, western blot analysis, promoter activity assays and chromatin immunoprecipitation analysis were performed in this study. Our data demonstrated that ethanol significantly increased Slc7a11 mRNA and protein expression in mouse hepatic stellate cells. Deletion of 20‐bp DNA sequence between −2044 to −2024 upstream of the transcription start site significantly increased the basal activity, and completely abolished the ethanol‐induced activity of the Slc7a11 promoter. DNA sequence analysis reveals a biding motif for octamer‐binding transcription factor 1 (OCT‐1) in this deleted fragment. Similarly, mutation of this OCT‐1 binding motif significantly increased the basal promoter activity and abolished the response to ethanol. In addition, Ethanol exposure significantly inhibited OCT‐1 binding to the Slc7a11 promoter region, while the OCT‐1 mRNA and protein levels were comparable in cells treated with or without ethanol. Results from the present study suggest that OCT‐1 functions as a repressor on the Slc7a11 promoter, and that ethanol inhibits OCT‐1 binding to the Slc7a11 promoter, and therefore increases Slc7a11 expression. Grant support: R01HL089382 (ZhongMao Guo) and SC1HL101431 (Hong Yang).