Zinc ions promote prestalk-to-stalk and prespore-to-stalk conversions in Dictyostelium discoideum

Abstract

To clarify the mechanism of stalk cell differentiation in Dictyostelium discoideum (strain NC4), we have examined the effects of Zn 2+ on in vitro cell differentiation of prestalk and prespore cells isolated from normally formed slugs. Prestalk cells did not differentiate into stalk cells under submerged conditions, but in the presence of the stalk-inducing factor-1 (DIF-1) at 100 nM or Zn 2+ at 5 mM, a small number of the cells (< 15%) differentiated into stalk cells. Interestingly, Zn 2+ in combination with DIF-1 induced the prestalk-to-stalk conversion at high efficiencies (approx. 60%). Furthermore, isolated prespore cells were also converted to stalk cells at high efficiencies (approx. 50%) in the presence of both DIF-1 and Zn 2+, while the conversion poorly occurred in the absence of Zn 2+. These results indicate that Zn 2+ may mimic some cellular interaction(s) which are required for stalk cell formation in this strain.