Activation of sterol regulatory element-binding protein 1c and fatty acid synthase transcription by hepatitis C virus non-structural protein 2

J Gen Virol. 2008 May;89(Pt 5):1225-1230. doi: 10.1099/vir.0.83491-0.

Abstract

Transcriptional factor sterol regulatory element-binding protein 1c (SREBP-1c) activates the transcription of lipogenic genes, including fatty acid synthase (FAS). Hepatitis C virus (HCV) infection is often associated with lipid accumulation within the liver, known as steatosis in the clinic. The molecular mechanisms of HCV-associated steatosis are not well characterized. Here, we showed that HCV non-structural protein 2 (NS2) activated SREBP-1c transcription in human hepatic Huh-7 cells as measured by using a human SREBP-1c promoter-luciferase reporter plasmid. We further showed that sterol regulatory element (SRE) and liver X receptor element (LXRE) in the SREBP-1c promoter were involved in SREBP-1c activation by HCV NS2. Furthermore, expression of HCV NS2 resulted in the upregulation of FAS transcription. We also showed that FAS upregulation by HCV NS2 was SREBP-1-dependent since deleting the SRE sequence in a FAS promoter and expressing a dominant-negative SREBP-1 abrogated FAS promoter upregulation by HCV NS2. Taken together, our results suggest that HCV NS2 can upregulate the transcription of SREBP-1c and FAS, and thus is probably a contributing factor for HCV-associated steatosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Artificial Gene Fusion
  • Cell Line
  • Fatty Acid Synthases / biosynthesis*
  • Genes, Reporter
  • Hepacivirus / physiology*
  • Humans
  • Luciferases / biosynthesis
  • Luciferases / genetics
  • Sterol Regulatory Element Binding Proteins / biosynthesis*
  • Transcription, Genetic*
  • Viral Nonstructural Proteins / physiology*

Substances

  • NS2 protein, Hepatitis C virus
  • Sterol Regulatory Element Binding Proteins
  • Viral Nonstructural Proteins
  • Luciferases
  • Fatty Acid Synthases