title: Analysis of the maturation process of prestalk cells in Dictyostelium discoideum.
abstract: The requirements for the terminal differentiation process of the stalk pathway (from prestalk to stalk) of Dictyostelium discoideum were analyzed by using a low-cell-density culture system with prestalk cells isolated from normally developed slugs. Any of the substances, such as differentiation-inducing factor-1 (DIF-1), DIF-2, dimethyloxazolidinedione, and adenosine, that had been shown to promote prestalk/stalk differentiation did not cause an efficient and consistent induction of prestalk-to-stalk conversion, either alone or in combination. However, the addition of 8-bromoadenosine 3',5'-cyclic monophosphate (Br-cAMP) resulted in high efficiency (80-90%) of stalk cell formation which accompanied the accumulation of a stalk-specific protein, wst34. The maturation process was inhibited by Ca2+ but not by Mg2+. More importantly, the Br-cAMP-induced stalk cell differentiation was neither inhibited nor promoted by DIF-1, cAMP, or ammonia and occurred even at very low cell densities if only Br-cAMP was supplied. Since Br-cAMP is though to penetrate into the cells and to activate the intracellular protein kinase A, the present results suggest that the activation of protein kinase A is sufficient for prestalk-to-stalk conversion.
authors.affiliation: Department of Botany, Faculty of Science, Kyoto University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kubohara
authors.forename: M
authors.initials: M
authors.lastname: Maeda
authors.forename: K
authors.initials: K
authors.lastname: Okamoto
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000241:Adenosine; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured / Q000187:drug effects; D004023:Dictyostelium / Q000254:growth & development*; D004114:Dimethadione; D006588:Hexanones / Q000494:pharmacology; D010422:Pentanones / Q000494:pharmacology; D011494:Protein Kinases / Q000502:physiology
chemical_list: D006588:Hexanones; D010422:Pentanones; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; C055365:1-(3,5-dichloro-2,6-dihydroxy-4-methoxyphenyl-)-1-pentanone; D015124:8-Bromo Cyclic Adenosine Monophosphate; D004114:Dimethadione; D011494:Protein Kinases; D000241:Adenosine; D002118:Calcium