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Cell type regulation in response to expression of ricin A in Dictyostelium

G Shaulsky1, W F Loomis

  • 1Department of Biology, University of California at San Diego, La Jolla 92093.

Developmental Biology
|November 1, 1993
PubMed

Insights

Dictyostelium discoideum cell-type regulation involves prespore cells inhibiting prestalk cell conversion. Poisoning prespore cells triggers prestalk-to-prespore cell conversion and subsequent cell death.

Area of Science:

  • Cellular and developmental biology
  • Molecular biology
  • Biochemistry

Background:

  • Dictyostelium discoideum serves as a model organism for studying cellular differentiation and morphogenesis.
  • Cell-type differentiation into prespore and prestalk cells is crucial for fruiting body formation.

Purpose of the Study:

  • To investigate the regulatory mechanisms governing cell-type determination in Dictyostelium discoideum.
  • To determine if cell-type conversion occurs in response to targeted cell lethality.

Main Methods:

  • Utilized a ricin A toxin gene expressed under cell-type specific promoters (prespore and prestalk).
  • Analyzed the effects of targeted cell lethality on cell-type differentiation and fruiting body development.
  • Observed cell conversion by monitoring gene expression and cell fate.

Main Results:

  • Expression of ricin A in prespore cells led to cell death and subsequent conversion of prestalk cells into prespore cells.
  • Expression of ricin A in prestalk cells resulted in non-culminating fruiting bodies with normal spore formation.
  • Prespore cells appear to inhibit the conversion of prestalk cells to prespore cells, suggesting an inhibitory signaling mechanism.

Conclusions:

  • Prespore cells exert inhibitory control over prestalk cell differentiation into prespore cells.
  • This regulation is mediated by a secreted inhibitor produced by prespore cells, to which they are insensitive.
  • The findings reveal a novel regulatory feedback loop in Dictyostelium discoideum development.

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