, Volume 6, Issue 4, pp 291–297 | Cite as

BAPTA blocks DNA fragmentation and chromatin condensation downstream of caspase-3 and DFF activation in HT-induced apoptosis in HL-60 cells

  • Min Zhang
  • Yanping Li
  • Hongqing Zhang
  • Shaobai Xue


DFF ((DNA Fragmentation Factor) is a heterodimer composed of 40 kDa (DFF40, CAD) and 45 kDa (DFF45, ICAD) subunits. During apoptosis, activated caspase-3 cleaves DFF45 and activates DFF40, a DNase that targets nucleosomal linker region and cleaves chromatin DNA into nucleosomal fragments. We have previously reported that HT induced apoptosis in HL-60 cells, and intracellular Ca2+ chelator BAPTA blocked apoptosis-associated DNA fragmentation induced by HT. We report here that HT also induced activation of caspase-3 and cleavage of DFF45. BAPTA prevented neither the caspase-3 activation nor the cleavage of DFF45. Mitochondrial membrane potential was disrupted in BAPTA-AM treated cells. However, BAPTA did prevent DNA fragmentation and chromatin condensation in HT-treated cells. These data suggest a novel role for intracellular calcium in regulating apoptotic nuclease that causes DNA fragmentation and chromatin condensation.

apoptosis Ca2+ caspase-3 DFF BAPTA-AM mitochondrial membrane potential 


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Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Min Zhang
    • 1
  • Yanping Li
    • 1
  • Hongqing Zhang
    • 1
  • Shaobai Xue
    • 2
  1. 1.Department of BiologyBeijing Normal UniversityBeijingPeople's Republic of China
  2. 2.Department of BiologyBeijing Normal UniversityBeijingPeople's Republic of China

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