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Baculovirus p33 binds human p53 and enhances p53-mediated apoptosis

G G Prikhod'ko1, Y Wang, E Freulich

  • 1Departments of Entomology and Genetics, University of Georgia, Athens, Georgia 30602, USA.

Journal of Virology
|January 9, 1999
PubMed

Insights

Human p53 induces apoptosis in insect cells and interacts with baculovirus protein p33. Co-expression with p33 enhances p53-mediated apoptosis, revealing p33

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Virology

Background:

  • The tumor suppressor protein p53 is crucial for regulating cell cycle, apoptosis, and differentiation in vertebrates.
  • Baculoviruses, such as Autographa californica nuclear polyhedrosis virus (AcMNPV), are widely used in insect cell culture for protein expression.
  • Understanding viral-host interactions is key to optimizing expression systems and uncovering novel biological functions.

Purpose of the Study:

  • To investigate the interaction between human p53 and baculovirus proteins in insect cells.
  • To determine the effect of human p53 expression on insect cell apoptosis and growth.
  • To elucidate the role of baculovirus protein p33 in modulating p53-induced cell death.

Main Methods:

  • Expression of human p53 and baculovirus proteins (p33, p35, OpIAP, CpIAP) in insect SF-21 and TN-368 cells.
  • Co-immunoprecipitation to confirm protein-protein interactions.
  • Confocal microscopy to analyze protein localization.
  • Assessment of apoptosis using morphological features and DNA fragmentation assays.
  • Cell growth inhibition assays.

Main Results:

  • Human p53 formed a stable complex with the baculovirus protein p33.
  • p53 induced apoptosis in insect cells, characterized by nuclear condensation, fragmentation, and blebbing.
  • Co-expression with p33 significantly enhanced p53-mediated apoptosis (approximately twofold).
  • Baculovirus inhibitors of apoptosis (p35, OpIAP, CpIAP) blocked p53-induced apoptosis.
  • p53 expression inhibited cell growth, an effect not significantly altered by p33.

Conclusions:

  • Human p53 influences both insect cell growth and death pathways.
  • Baculovirus protein p33 interacts with p53 and modulates its apoptotic effects in insect cells.
  • This interaction provides insights into viral manipulation of host cell processes and potential applications in biotechnology.

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