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Apoptosis-inducing proteins in chicken anemia virus and TT virus

M H de Smit1, M H M Noteborn

  • 1Department of Molecular Genetics, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands. m.smit@chem.leidenuniv.nl

Current Topics in Microbiology and Immunology
|February 24, 2009
PubMed

Insights

Torque teno viruses (TTVs) possess a protein, TAIP, that induces apoptosis in human tumor cells, similar to chicken anemia virus

Area of Science:

  • Virology
  • Molecular Biology
  • Oncology

Background:

  • Torque teno viruses (TTVs) exhibit genomic similarities to chicken anemia virus (CAV).
  • CAV encodes the protein apoptin, known for inducing apoptosis in human tumor cells.
  • Apoptin demonstrates broad-spectrum apoptosis induction in diverse human tumor cell lines.

Purpose of the Study:

  • To investigate a putative TTV open reading frame (ORF) in TTV genotype 1, named TAIP.
  • To compare the apoptosis-inducing capabilities of TAIP with CAV's apoptin.
  • To analyze the conservation and potential therapeutic relevance of TAIP.

Main Methods:

  • Functional studies of TAIP in various human hepatocarcinoma and non-hepatocarcinoma cell lines.
  • Comparative analysis of TAIP and apoptin's apoptosis-inducing activity.
  • Detailed sequence analysis of the TAIP ORF and its N-terminal half (N-TAIP) across TTV isolates.

Main Results:

  • TAIP induces p53-independent apoptosis in human hepatocarcinoma cell lines, comparable to apoptin.
  • TAIP's apoptotic effect is less pronounced in non-hepatocarcinoma cell lines compared to apoptin.
  • The TAIP ORF is conserved in a subset of TTVs, while N-TAIP is broadly conserved among TTV isolates.

Conclusions:

  • TAIP represents a TTV-encoded protein with significant apoptosis-inducing potential, particularly in liver cancer cells.
  • The conserved N-TAIP region suggests a potential role in TTV biology and possible therapeutic applications.
  • Further research into TAIP and apoptin similarities may offer insights into disease development and treatment strategies.

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