Identification of DNA-protein interactions in the 5 ' flanking and 5 ' untranslated regions of the human multidrug resistance protein (MRP1) gene: Evaluation of a putative antioxidant response element/AP-1 binding site
Eu. Kurz et al., Identification of DNA-protein interactions in the 5 ' flanking and 5 ' untranslated regions of the human multidrug resistance protein (MRP1) gene: Evaluation of a putative antioxidant response element/AP-1 binding site, BIOC BIOP R, 285(4), 2001, pp. 981-990
Citations number
46
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Overexpression of the multidrug resistance protein, MRP1, confers resistanc
e to multiple natural product-type chemotherapeutics. MRP1 amplification is
observed in some multidrug-resistant cell lines, while in others, increase
d transcription occurs in the absence of gene amplification. To investigate
mechanisms influencing MRP1 transcription, three small cell lung cancer ce
ll lines were examined: drug sensitive H69 cells with two apparently normal
MRP1 alleles, highly resistant H69AR cells in which MRP1 is amplified and
low level resistant H69PR cells that contain only one MRP1 allele. Deoxyrib
onuclease 1 footprinting and gel mobility shift assays were undertaken usin
g nuclear extracts from the three cell lines and a 1 kb region encompassing
the 5 ' flanking region of MRP1. Thirteen protein binding sites were ident
ified of which six were sequence specific. Differences in levels of protein
binding occurred with a putative antioxidant response element (ARE)/AP-1 b
inding site at -511 to -477. Levels of protein binding to this site were 2.
5- to 3.0-fold higher in H69AR nuclear extracts versus extracts from H69 or
H69PR cells. The AP-1 sequence is required for binding and c-Jun and JunD
were identified as components of the protein complex. The ARE/AP-1 element
functioned as a transcriptional enhancer but did not mediate induction of a
luciferase reporter gene upon beta -naphthoflavone treatment. (C) 2001 Aca
demic Press.