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Expression of bacterial cytotoxin genes in mammalian target cells

W Wels1, M Baldrich, T Chakraborty

  • 1Theodor-Boveri-Institut für Biowissenschaften (Biozentrum), Lehrstuhl für Mikrobiologie, Universität Würzburg, Germany.

Molecular Microbiology
|September 1, 1992
PubMed

Insights

Bacterial toxins like exotoxin A (ETA) and adenylate cyclase toxin (CYA) were lethal when expressed in mammalian cells. However, pertussis toxin (PT) subunit S1 was tolerated, suggesting it may not effectively target G-proteins in vivo.

Area of Science:

  • Microbiology
  • Cell Biology
  • Toxicology

Background:

  • Bacterial toxins play a significant role in pathogenesis.
  • Understanding toxin expression in host cells is crucial for developing countermeasures.
  • Pseudomonas aeruginosa exotoxin A (ETA) and Bordetella pertussis toxins (pertussis toxin [PT] and adenylate cyclase toxin [CYA]) are key virulence factors.

Purpose of the Study:

  • To investigate the expression of active bacterial cytotoxin gene fragments in mammalian cells.
  • To determine the cellular effects and viability of mammalian cells producing these toxins.
  • To assess the potential for endogenous expression of pertussis toxin subunit S1 (PTS1).

Main Methods:

  • Gene fragments encoding the active portions of ETA, PT, and CYA were introduced into mammalian target cells.
  • Cell viability and stability of transfectants expressing these toxin genes were assessed.
  • Comparative analysis of expression effects for ETA, CYA, and PTS1.

Main Results:

  • Expression of active exotoxin A (ETA) and adenylate cyclase toxin (CYA) was lethal to producing mammalian cells.
  • Stable transfectants of Cos-1 cells expressing active ETA or CYA could not be obtained.
  • The expression of the pertussis toxin S1 subunit (PTS1) was tolerated by producing mammalian cells.

Conclusions:

  • Active ETA and CYA are highly cytotoxic to mammalian cells, preventing stable expression.
  • Mammalian cells tolerate the expression of PTS1, suggesting it may not efficiently interact with cellular G-proteins or require additional subunits for in vivo ADP-ribosylation activity.

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