Transcriptional Activation of a Constitutive Heterochromatic Domain of the Human Genome in Response to Heat Shock

Nicoletta Rizzi, Marco Denegri, Ilaria Chiodi, Margherita Corioni, Rut Valgardsdottir, Fabio Cobianchi, Silvano Riva, Giuseppe Biamonti

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Abstract

Heat shock triggers the assembly of nuclear stress bodies that contain heat shock factor 1 and a subset of RNA processing factors. These structures are formed on the pericentromeric heterochromatic regions of specific human chromosomes, among which chromosome 9. In this article we show that these heterochromatic domains are characterized by an epigenetic status typical of euchromatic regions. Similarly to transcriptionally competent portions of the genome, stress bodies are, in fact, enriched in acetylated histone H4. Acetylation peaks at 6 h of recovery from heat shock. Moreover, heterochromatin markers, such as HP1 and histone H3 methylated on lysine 9, are excluded from these nuclear districts. In addition, heat shock triggers the transient accumulation of RNA molecules, heterogeneous in size, containing the subclass of satellite III sequences found in the pericentromeric heterochromatin of chromosome 9. This is the first report of a transcriptional activation of a constitutive heterochromatic portion of the genome in response to stress stimuli.

Original languageEnglish
Pages (from-to)543-551
Number of pages9
JournalMolecular Biology of the Cell
Volume15
Issue number2
DOIs
Publication statusPublished - Feb 2004

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ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

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