Loss of heterochromatin protein 1 (HP1) chromodomain function in mammalian cells by intracellular antibodies causes cell death

Ilaria Filesi, Alessio Cardinale, Sjaak van der Sar, Ian G Cowell, Prim B Singh, Silvia Biocca

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


The chromodomain (CD) is a highly conserved motif present in a variety of animal and plant proteins, and its probable role is to assemble a variety of macromolecular complexes in chromatin. The importance of the CD to the survival of mammalian cells has been tested. Accordingly, we have ablated CD function using two single-chain intracellular Fv (scFv) fragments directed against non-overlapping epitopes within the HP1 CD motif. The scFv fragments can recognize both CD motifs of HP1 and Polycomb (Pc) in vitro and, when expressed intracellularly, interact with and dislodge the HP1 protein(s) from their heterochromatin localization in vivo. Mouse and human fibroblasts expressing anti-chromodomain scFv fragments show a cell-lethal phenotype and an apoptotic morphology becomes apparent soon after transfection. The mechanism of cell death appears to be p53 independent, and the cells are only partly rescued by incubation with the wide spectrum caspase inhibitor Z-VAD fmk. We conclude that expression of anti-chromodomain intracellular antibodies is sufficient to trigger a p53-independent apoptotic pathway that is only partly dependent on the known Z-VAD-inhibitable caspases, suggesting that CD function is essential for cell survival.

Original languageEnglish
Pages (from-to)1803-13
Number of pages11
JournalJournal of Cell Science
Issue numberPt 9
Publication statusPublished - May 1 2002


  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Annexin A5
  • COS Cells
  • Cell Death
  • Cell Nucleus
  • Chromatin
  • Chromosomal Proteins, Non-Histone
  • Cloning, Molecular
  • Enzyme Inhibitors
  • Epitopes
  • Eukaryotic Cells
  • Humans
  • Macromolecular Substances
  • Mammals
  • Mice
  • Mutation
  • Peptide Fragments
  • Phenotype
  • Precipitin Tests
  • Protein Binding
  • Protein Structure, Tertiary
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53
  • Journal Article
  • Research Support, Non-U.S. Gov't

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