Target genes of Topoisomerase IIβ regulate neuronal survival and are defined by their chromatin state

Proc Natl Acad Sci U S A. 2012 Apr 17;109(16):E934-43. doi: 10.1073/pnas.1119798109. Epub 2012 Apr 2.

Abstract

Topoisomerases are essential for DNA replication in dividing cells, but their genomic targets and function in postmitotic cells remain poorly understood. Here we show that a switch in the expression from Topoisomerases IIα (Top2α) to IIβ (Top2β) occurs during neuronal differentiation in vitro and in vivo. Genome-scale location analysis in stem cell-derived postmitotic neurons reveals Top2β binding to chromosomal sites that are methylated at lysine 4 of histone H3, a feature of regulatory regions. Indeed Top2β-bound sites are preferentially promoters and become targets during the transition from neuronal progenitors to neurons, at a time when cells exit the cell cycle. Absence of Top2β protein or its activity leads to changes in transcription and chromatin accessibility at many target genes. Top2β deficiency does not impair stem cell properties and early steps of neuronal differentiation but causes premature death of postmitotic neurons. This neuronal degeneration is caused by up-regulation of Ngfr p75, a gene bound and repressed by Top2β. These findings suggest a chromatin-based targeting of Top2β to regulatory regions in the genome to govern the transcriptional program associated with neuronal differentiation and longevity.

Publication types

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

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Differentiation / genetics
  • Cell Survival / genetics
  • Cells, Cultured
  • Chromatin / genetics*
  • DNA Topoisomerases, Type II / genetics*
  • DNA Topoisomerases, Type II / metabolism
  • DNA-Binding Proteins / antagonists & inhibitors
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Diketopiperazines
  • Embryonic Stem Cells / cytology
  • Embryonic Stem Cells / drug effects
  • Embryonic Stem Cells / metabolism
  • Female
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental
  • Immunoprecipitation
  • Male
  • Mice
  • Mice, 129 Strain
  • Mice, Knockout
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / metabolism*
  • Oligonucleotide Array Sequence Analysis
  • Piperazines / pharmacology
  • Protein Binding
  • RNA Interference
  • Receptor, Nerve Growth Factor / genetics
  • Receptor, Nerve Growth Factor / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Time Factors
  • Topoisomerase II Inhibitors / pharmacology

Substances

  • Chromatin
  • DNA-Binding Proteins
  • Diketopiperazines
  • Piperazines
  • Receptor, Nerve Growth Factor
  • Topoisomerase II Inhibitors
  • 4,4'-(1,2-dimethyl-1,2-ethanediyl)bis-2,6-piperazinedione
  • DNA Topoisomerases, Type II

Associated data

  • GEO/GSE25533
  • GEO/GSE27245
  • GEO/GSE27246