DNA supercoiling in apoptotic chromatin

Cristina D'Arrigo, Paola Barboro, Michele Mormino, Rosella Coradeghini, Silvio Parodi, Eligio Patrone, Cecilia Balbi

Research output: Contribution to journalArticlepeer-review


In a previous paper, we have reported that in rat thymocyte apoptosis chromatin undergoes a specific structural change as well as an appreciable increase in the unacetylated forms of histones H3 and H4. Here, we show that H3 and H4 deacetylation bears no relation to chromatin condensation, and present new ultrastructural and topological observations that largely clarify the organization of the condensed state. The texture of the latter corresponds to a closely woven network of negatively supercoiled 11nm fibers, as shown by both ultrastructural observations and relaxation experiments using ethidium bromide. Circularly closed chromatin loops undergoing apoptotic condensation, clearly showing nucleosome compact dimers or higher oligomers, as well as long stretches of supercoiled DNA, have also been detected. All of these modifications are strongly reminiscent of the alterations induced in nucleosome bearing plasmids by the chromatin remodeling factors SWI/SNF and RSC.

Original languageEnglish
Pages (from-to)540-546
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number3
Publication statusPublished - Sep 26 2003


  • Apoptosis
  • Butyrate
  • Chromatin structure
  • DNA supercoiling

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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