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Scientific article
Open access
English

Dominant-negative suppression of HNF-1alpha function results in defective insulin gene transcription and impaired metabolism-secretion coupling in a pancreatic beta-cell line

Published inEMBO journal, vol. 17, no. 22, p. 6701-6713
Publication date1998
Abstract

Mutations in the hepatocyte nuclear factor-1alpha (HNF-1alpha) have been linked to subtype 3 of maturity-onset diabetes of the young (MODY3), which is characterized by a primary defect in insulin secretion. The role of HNF-1alpha in the regulation of pancreatic beta-cell function was investigated. Gene manipulation allowed graded overexpression of HNF-1alpha and controlled dominant-negative suppression of HNF-1alpha function in insulinoma INS-1 cells. We show that HNF-1alpha is essential for insulin gene transcription, as demonstrated by a pronounced decrease in insulin mRNA expression and in insulin promoter activity under dominant-negative conditions. The expression of genes involved in glucose transport and metabolism including glucose transporter-2 and L-type pyruvate kinase is also regulated by HNF-1alpha. Loss of HNF-1alpha function leads to severe defects in insulin secretory responses to glucose and leucine, resulting from impaired glucose utilization and mitochondrial oxidation. The nutrient-evoked ATP production and subsequent changes in plasma membrane potential and intracellular Ca2+ were diminished by suppression of HNF-1alpha function. These results suggest that HNF-1alpha function is essential for maintaining insulin storage and nutrient-evoked release. The defective mitochondrial oxidation of metabolic substrates causes impaired insulin secretion, indicating a molecular basis for the diabetic phenotype of MODY3 patients.

Keywords
  • Adenosine Triphosphate/biosynthesis
  • Base Sequence
  • Binding Sites
  • Calcium/metabolism
  • Cell Line
  • Cell Membrane/physiology
  • DNA Primers
  • DNA-Binding Proteins
  • Down-Regulation
  • Genes, Dominant
  • Glucose/metabolism
  • Hepatocyte Nuclear Factor 1
  • Hepatocyte Nuclear Factor 1-alpha
  • Hepatocyte Nuclear Factor 1-beta
  • Humans
  • Insulin/genetics
  • Islets of Langerhans/cytology/metabolism
  • Leucine/metabolism
  • Membrane Potentials
  • Nuclear Proteins
  • Promoter Regions, Genetic
  • Transcription Factors/genetics/metabolism
  • Transcription, Genetic
  • Tumor Cells, Cultured
Citation (ISO format)
WANG, Haiyan et al. Dominant-negative suppression of HNF-1alpha function results in defective insulin gene transcription and impaired metabolism-secretion coupling in a pancreatic beta-cell line. In: EMBO journal, 1998, vol. 17, n° 22, p. 6701–6713. doi: 10.1093/emboj/17.22.6701
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Article (Published version)
accessLevelPublic
Identifiers
ISSN of the journal0261-4189
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269downloads

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