Beta-globin active chromatin Hub formation in differentiating erythroid cells and in p45 NF-E2 knock-out mice

J Biol Chem. 2007 Jun 1;282(22):16544-52. doi: 10.1074/jbc.M701159200. Epub 2007 Apr 11.

Abstract

Expression of the beta-globin genes proceeds from basal to exceptionally high levels during erythroid differentiation in vivo. High expression is dependent on the locus control region (LCR) and coincides with more frequent LCR-gene contacts. These contacts are established in the context of an active chromatin hub (ACH), a spatial chromatin configuration in which the LCR, together with other regulatory sequences, loops toward the active beta-globin-like genes. Here, we used recently established I/11 cells as a model system that faithfully recapitulates the in vivo erythroid differentiation program to study the molecular events that accompany and underlie ACH formation. Upon I/11 cell induction, histone modifications changed, the ACH was formed, and the beta-globin-like genes were transcribed at rates similar to those observed in vivo. The establishment of frequent LCR-gene contacts coincided with a more efficient loading of polymerase onto the beta-globin promoter. Binding of the transcription factors GATA-1 and EKLF to the locus, although previously shown to be required, was not sufficient for ACH formation. Moreover, we used knock-out mice to show that the erythroid transcription factor p45 NF-E2, which has been implicated in beta-globin gene regulation, is dispensable for beta-globin ACH formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / physiology*
  • Cells, Cultured
  • Chromatin / metabolism
  • Chromatin Assembly and Disassembly / physiology*
  • Erythroid Cells / cytology
  • Erythroid Cells / metabolism*
  • GATA1 Transcription Factor / metabolism
  • Globins / biosynthesis*
  • Globins / genetics
  • Histones / metabolism
  • Kruppel-Like Transcription Factors / metabolism
  • Locus Control Region / physiology*
  • Mice
  • Mice, Knockout
  • Models, Biological
  • NF-E2 Transcription Factor, p45 Subunit / deficiency
  • NF-E2 Transcription Factor, p45 Subunit / metabolism*
  • Promoter Regions, Genetic / physiology
  • Quantitative Trait Loci / physiology

Substances

  • Chromatin
  • GATA1 Transcription Factor
  • Histones
  • Kruppel-Like Transcription Factors
  • NF-E2 Transcription Factor, p45 Subunit
  • Nfe2 protein, mouse
  • erythroid Kruppel-like factor
  • Globins