Pancreatic β cell enhancers regulate rhythmic transcription of genes controlling insulin secretion

Science. 2015 Nov 6;350(6261):aac4250. doi: 10.1126/science.aac4250.

Abstract

The mammalian transcription factors CLOCK and BMAL1 are essential components of the molecular clock that coordinate behavior and metabolism with the solar cycle. Genetic or environmental perturbation of circadian cycles contributes to metabolic disorders including type 2 diabetes. To study the impact of the cell-autonomous clock on pancreatic β cell function, we examined pancreatic islets from mice with either intact or disrupted BMAL1 expression both throughout life and limited to adulthood. We found pronounced oscillation of insulin secretion that was synchronized with the expression of genes encoding secretory machinery and signaling factors that regulate insulin release. CLOCK/BMAL1 colocalized with the pancreatic transcription factor PDX1 within active enhancers distinct from those controlling rhythmic metabolic gene networks in liver. We also found that β cell clock ablation in adult mice caused severe glucose intolerance. Thus, cell type-specific enhancers underlie the circadian control of peripheral metabolism throughout life and may help to explain its dysregulation in diabetes.

Publication types

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

MeSH terms

  • ARNTL Transcription Factors / genetics
  • ARNTL Transcription Factors / metabolism
  • Animals
  • CLOCK Proteins / metabolism
  • Circadian Rhythm / genetics*
  • Diabetes Mellitus, Type 2 / genetics
  • Diabetes Mellitus, Type 2 / metabolism
  • Enhancer Elements, Genetic / physiology*
  • Exocytosis / genetics
  • Gene Expression Regulation*
  • Glucose Intolerance
  • Homeodomain Proteins / metabolism
  • Humans
  • Insulin / metabolism*
  • Insulin Secretion
  • Insulin-Secreting Cells / metabolism*
  • Liver / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Trans-Activators / metabolism
  • Transcription, Genetic

Substances

  • ARNTL Transcription Factors
  • Arntl protein, mouse
  • Homeodomain Proteins
  • Insulin
  • Trans-Activators
  • pancreatic and duodenal homeobox 1 protein
  • CLOCK Proteins
  • Clock protein, mouse

Associated data

  • GEO/GSE69889
  • GEO/GSE70960