Characterization of pancreatic transcription factor Pdx-1 binding sites using promoter microarray and serial analysis of chromatin occupancy

J Biol Chem. 2007 Nov 2;282(44):32084-92. doi: 10.1074/jbc.M700899200. Epub 2007 Aug 30.

Abstract

The homeobox transcription factor Pdx-1 is necessary for pancreas organogenesis and beta cell function, however, most Pdx-1-regulated genes are unknown. To further the understanding of Pdx-1 in beta cell biology, we have characterized its genomic targets in NIT-1 cells, a mouse insulinoma cell line. To identify novel targets, we developed a microarray that includes traditional promoters as well as non-coding conserved elements, micro-RNAs, and elements identified through an unbiased approach termed serial analysis of chromatin occupancy. In total, 583 new Pdx-1 target genes were identified, many of which contribute to energy sensing and insulin release in pancreatic beta cells. By analyzing 31 of the protein-coding Pdx-1 target genes, we show that 29 are expressed in beta cells and, of these, 68% are down- or up-regulated in cells expressing a dominant negative mutant of Pdx-1. We additionally show that many Pdx-1 targets also interact with NeuroD1/BETA2, including the micro-RNA miR-375, a known regulator of insulin secretion.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Binding Sites
  • Cell Differentiation
  • Chromatin / metabolism*
  • Chromatin Immunoprecipitation
  • Homeodomain Proteins / metabolism*
  • Insulin
  • Insulin-Secreting Cells / cytology
  • Insulin-Secreting Cells / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • MicroRNAs / metabolism
  • Oligonucleotide Array Sequence Analysis
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic*
  • Trans-Activators / metabolism*
  • Transcription, Genetic

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Chromatin
  • Homeodomain Proteins
  • Insulin
  • MicroRNAs
  • Neurod1 protein, mouse
  • Trans-Activators
  • pancreatic and duodenal homeobox 1 protein