Modeling apoptotic chromatin condensation in normal cell nuclei. Requirement for intranuclear mobility and actin involvement

Piotr Widlak, Olena Palyvoda, Slawomir Kumala, William T. Garrard

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Hallmarks of the terminal stages of apoptosis are genomic DNA fragmentation and chromatin condensation. Here, we have studied the mechanism of condensation both in vitro and in vivo. We found that DNA fragmentation per se of isolated nuclei from non-apoptotic cells induced chromatin condensation that closely resembles the morphology seen in apoptotic cells, independent of ATP utilization, at physiological ionic strengths. Interestingly, chromatin condensation was accompanied by release of nuclear actin, and both condensation and actin release could be blocked by reversibly pretreating nuclei with Ca2+, Cu2+, diamide, or low pH, procedures shown to stabilize internal nuclear components. Moreover, specific inhibition of nuclear F-actin depolymerization or promotion of its formation also reduced chromatin condensation. Chromatin condensation could also be inhibited by exposing nuclei to reagents that bind to the DNA minor groove, disrupting native nucleosomal DNA wrapping. In addition, in cultured cells undergoing apoptosis, drugs that inhibit depolymerization of actin or bind to the minor groove also reduced chromatin condensation, but not DNA fragmentation. Therefore, the ability of chromatin fragments with intact nucleosomes to form large clumps of condensed chromatin during apoptosis requires the apparent disassembly of internal nuclear structures that may normally constrain chromosome subdomains in non-apoptotic cells.

Original languageEnglish (US)
Pages (from-to)21683-21690
Number of pages8
JournalJournal of Biological Chemistry
Issue number24
StatePublished - Jun 14 2002

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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