Nucleoplasmin regulates chromatin condensation during apoptosis

Zhigang Lu, Chuanmao Zhang, Zhonghe Zhai

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Although chromatin condensation is one of the hallmarks of apoptosis, its relationship with DNA fragmentation has been controversial. We show here that apoptotic chromatin condensation is regulated by nucleoplasmin, a protein that decondenses sperm chromatin during male pronuclear assembly. In Xenopus egg extracts, nucleoplasmin is tyrosine-dephosphorylated during apoptosis. This dephosphorylation inactivates the chromatin decondensation activity of nucleoplasmin and leads to its exclusion from the chromatin. Inhibition of tyrosine dephosphorylation prevents apoptotic chromatin condensation but not DNA fragmentation. Studies with mutant proteins indicate that dephosphorylation of nucleoplasmin at Tyr-124 regulates chromatin condensation through changes in the interaction of nucleoplasmin with chromatin and the loss of its chromatin decondensation activity. These results show that chromatin condensation and DNA fragmentation are independent processes.

Original languageEnglish (US)
Pages (from-to)2778-2783
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
StatePublished - Feb 22 2005


  • Caspase
  • Nucleoplasmin
  • Protein tyrosine phosphatase

ASJC Scopus subject areas

  • General


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