Transactivation of the mouse sulfonylurea receptor I gene by BETA2/NeuroD

Mol Endocrinol. 2002 May;16(5):1097-107. doi: 10.1210/mend.16.5.0934.

Abstract

The sulfonylurea receptor 1 (SUR1) plays a key role in regulation of insulin secretion in pancreatic beta-cells. In this study we investigated the mechanism for tissue-specific expression of the SUR1 gene. A -138/-20 fragment exhibited basal promoter activity while the -660/-20 fragment contained a regulatory element for tissue-specific expression of the mouse SUR1 gene. A pancreatic beta-cell-specific transcription factor, BETA2 (beta-cell E box transcription factor)/NeuroD, enhanced the promoter activity of the -660/-20 fragment in cooperation with E47. Coexpression of a dominant negative mutant of BETA2/NeuroD, BETA2(1-233), repressed the promoter activity of the -660/-20 fragment. BETA2/NeuroD bound specifically to the E3 element located at -141. The E3 sequence in a heterologous context conferred transactivation by BETA2/NeuroD in HeLa and HIT cells. Mutation of E3 eliminated the stimulatory effect of BETA2/NeuroD. Unlike BETA2/NeuroD, neurogenin 3 (ngn3) could not activate the E3 element in HeLa cells. Overexpression of ngn3 concomitantly increased expression of BETA2/NeuroD and SUR1 in HIT cells but not in HeLa cells. These results indicate that BETA2/NeuroD induces tissue-specific expression of the SUR1 gene through the E3 element. These results also suggest that E3 is specific for BETA2/NeuroD, and the stimulatory effect of ngn3 in HIT cells may require factors specifically expressed in HIT cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters*
  • Animals
  • Base Sequence
  • Basic Helix-Loop-Helix Transcription Factors
  • Binding Sites
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / pharmacology*
  • Gene Expression
  • HeLa Cells
  • Humans
  • Insulinoma
  • Mice
  • Molecular Sequence Data
  • Mutagenesis
  • Pancreatic Neoplasms
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Potassium Channels / genetics*
  • Potassium Channels / metabolism
  • Potassium Channels, Inwardly Rectifying*
  • Promoter Regions, Genetic
  • Rats
  • Receptors, Drug / genetics*
  • Receptors, Drug / metabolism
  • Regulatory Sequences, Nucleic Acid
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sulfonylurea Receptors
  • Trans-Activators / metabolism
  • Trans-Activators / pharmacology*
  • Transcriptional Activation*
  • Transfection
  • Tumor Cells, Cultured

Substances

  • ABCC8 protein, human
  • ATP-Binding Cassette Transporters
  • Abcc8 protein, mouse
  • Abcc8 protein, rat
  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • NEUROD1 protein, human
  • Neurod1 protein, mouse
  • Peptide Fragments
  • Potassium Channels
  • Potassium Channels, Inwardly Rectifying
  • Receptors, Drug
  • Sulfonylurea Receptors
  • Trans-Activators