Elsevier

Kidney International

Volume 46, Issue 6, December 1994, Pages 1564-1566
Kidney International

Angiotensinogen
Transcription factors modulating angiotensinogen gene expression in hepatocytes

https://doi.org/10.1038/ki.1994.447Get rights and content
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Transcripting factors modulating angiotensinogen gene expression in hepatocytes. The gene encoding angiotensinogen is regulated at the transcriptional level in hepatocytes in response to glucocorticoids and inflammatory cytokines (IL-1 and TNF). These hormones activate transcription of the angiotensinogen gene by changing the abundance of DNA binding proteins that interact with a multihormone-inducible enhancer located between nucleotides -615 to -440 upstream of the major transcription start site. Activation of this enhancer in hepatocytes is effected by glucocorticoid- and cytokine-inducible DNA binding proteins. Cytokine induction is mediated through the interaction of two classes of transcription factors that bind to the acute-phase response element (APRE): nuclear factor-κB (NF-κB), and CCAAT-Box/Enhancer Binding Protein (C/EBP). NF-κB is a multiprotein DNA binding complex sequestered in the cytoplasm that is induced in the nucleus by cytokines, whereas C/EBP is a nuclear transcription factor family implicated in the expression of differentiated hepatic proteins. During the acute-phase response, individual C/EBP family members are discordinately regulated: C/EBPα levels fall, whereas another C/EBP family member termed nuclear factor IL6 (NF-IL6), is induced. We investigated the interaction between the two acute-phase induced APRE-binding proteins: NF-κB and NF-IL6. Both proteins bind to overlapping nucleotides in a mutually exclusive fashion with similar affinities for the APRE. NF-IL6, a less potent transactivator, attenuates NF-κB mediated transcription late in the evolution of the acute-phase response. These observations argue for a temporal model of sequentially-expressed transcription factors occupying the APRE during the evolution of the inflammatory process.

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