کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9882086 1536537 2005 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Identification of the promoter elements involved in the stimulation of ASCT2 expression by glutamine availability in HepG2 cells and the probable involvement of FXR/RXR dimers
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Identification of the promoter elements involved in the stimulation of ASCT2 expression by glutamine availability in HepG2 cells and the probable involvement of FXR/RXR dimers
چکیده انگلیسی
Expression of the glutamine transport protein ASCT2 in the human hepatoma cell line HepG2 is increased when cells are cultured in the presence of glutamine and this has been shown to be due to stimulation of the ASCT2 promoter. Analysis of a number of promoter constructs localised the activation site to be between bases −653 and −543. Gel shift assays identified an IR-1 repeat within a 24 bp region of this sequence which bound at least two nuclear proteins. Protein binding to this site was significantly higher in cells grown in glutamine-containing medium than when glutamine was absent. The identity of the higher molecular weight species binding to this promoter element was likely to be FXR/RXR dimers. Simultaneous overexpression of FXR and RXR increased the promoter activity in cells grown without glutamine to the same extent as did glutamine addition; the effects of glutamine and FXR/RXR expression were not additive. Mutagenesis of the FXR/RXR binding site in the promoter construct abolished glutamine and FXR/RXR stimulation. Real-time PCR showed levels of FXR mRNA were significantly increased in response to glutamine. The activity of the FXR promoter was also increased in response to glutamine. These results show that the stimulation of ASCT2 expression in response to glutamine in part involves binding of FXR/RXR to the ASCT2 promoter.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Archives of Biochemistry and Biophysics - Volume 443, Issues 1–2, 15 November 2005, Pages 53-59
نویسندگان
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