RTP801 is a newly discovered stress-response gene that is induced by hypoxia and other cell stress signals. Arsenic is a heavy metal that is linked to carcinogenesis in humans. Here, we investigated the mechanism by which arsenic induces RTP801 transcription. In HaCaT human keratinocytes, arsenite was able to induce a rapid rise in the RTP801 mRNA level. Correspondingly, arsenite treatment was capable of stimulating a 2.5 kb human RTP801 promoter. Such a stimulatory effect was inhibited by co-expression of superoxide dismutase or glutathione peroxidase, and was abrogated by N-acetylcysteine, implying that ROS (reactive oxygen species) were involved in transcriptional regulation of the RTP801 gene. A series of deletion studies with the promoter revealed a critical arsenic-responsive region between −1057 and −981 bp of the promoter. Point mutations of the putative Elk-1 site and the C/EBP (CCAAT/enhancer-binding protein) site within this region were able to reduce the stimulatory effect of arsenite, indicating that Elk-1 and C/EBP are involved in transcriptional regulation of the RTP801 gene by arsenite. Furthermore, a gel mobility-shift assay demonstrated that arsenite was able to mount the rapid formation of a protein complex that bound the arsenic-responsive region as well as the C/EBP-containing sequence. The arsenite stimulation on RTP801 transcription was partly mediated by the ERK (extracellular-signal-regulated kinase) pathway, since the effect of RTP801 was inhibited by a selective ERK inhibitor. In addition, overexpression of Elk-1 and C/EBPβ was able to elevate the promoter activity. Therefore these studies indicate that RTP801 is a transcriptional target of arsenic in human keratinocytes, and that arsenic and ROS production are linked to Elk-1 and C/EBP in the transcriptional control.
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Research Article|
November 08 2005
Arsenite induces a cell stress-response gene, RTP801, through reactive oxygen species and transcription factors Elk-1 and CCAAT/enhancer-binding protein
Lin Lin;
Lin Lin
*Department of Medical and Molecular Genetics, Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, IN 46202, U.S.A.
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Teresa M. Stringfield;
Teresa M. Stringfield
*Department of Medical and Molecular Genetics, Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, IN 46202, U.S.A.
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Xianglin Shi;
Xianglin Shi
†Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV 26505, U.S.A.
‡Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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Yan Chen
Yan Chen
1
*Department of Medical and Molecular Genetics, Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, IN 46202, U.S.A.
‡Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
1To whom correspondence should be addressed (email ychen3@iupui.edu).
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Publisher: Portland Press Ltd
Received:
April 05 2005
Revision Received:
June 10 2005
Accepted:
July 12 2005
Accepted Manuscript online:
July 12 2005
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London
2005
Biochem J (2005) 392 (1): 93–102.
Article history
Received:
April 05 2005
Revision Received:
June 10 2005
Accepted:
July 12 2005
Accepted Manuscript online:
July 12 2005
Citation
Lin Lin, Teresa M. Stringfield, Xianglin Shi, Yan Chen; Arsenite induces a cell stress-response gene, RTP801, through reactive oxygen species and transcription factors Elk-1 and CCAAT/enhancer-binding protein. Biochem J 15 November 2005; 392 (1): 93–102. doi: https://doi.org/10.1042/BJ20050553
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