title: Early nucleolar disorganization in Dictyostelium cell death.
abstract: Cell death occurs in all eukaryotes, but it is still not known whether some core steps of the cell death process are conserved. We investigated this using the protist Dictyostelium. The dissection of events in Dictyostelium vacuolar developmental cell death was facilitated by the sequential requirement for two distinct exogenous signals. An initial exogenous signal (starvation and cAMP) recruited some cells into clumps. Only within these clumps did subsequent cell death events take place. Contrary to our expectations, already this initial signal provoked nucleolar disorganization and irreversible inhibition of rRNA and DNA synthesis, reflecting marked cell dysfunction. The initial signal also primed clumped cells to respond to a second exogenous signal (differentiation-inducing factor-1 or c-di-GMP), which led to vacuolization and synthesis of cellulose encasings. Thus, the latter prominent hallmarks of developmental cell death were induced separately from initial cell dysfunction. We propose that (1) in Dictyostelium vacuolization and cellulose encasings are late, organism-specific, hallmarks, and (2) on the basis of our observations in this protist and of similar previous observations in some cases of mammalian cell death, early inhibition of rRNA synthesis and nucleolar disorganization may be conserved in some eukaryotes to usher in developmental cell death.
authors.affiliation: Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France.
authors.forename: M F
authors.initials: MF
authors.lastname: Luciani
authors.affiliation: Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Song
authors.affiliation: Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France.
authors.forename: A
authors.initials: A
authors.lastname: Sahrane
authors.affiliation: Microscopy Core Facility, FR3479 Institut de Microbiologie de la Méditerranée, CNRS, Marseille, France.
authors.forename: A
authors.initials: A
authors.lastname: Kosta
authors.affiliation: Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France.
authors.forename: P
authors.initials: P
authors.lastname: Golstein
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D001343:Autophagy / Q000235:genetics; D016923:Cell Death / Q000235:genetics*; D002466:Cell Nucleolus / Q000235:genetics* / Q000473:pathology; D000242:Cyclic AMP / Q000235:genetics; D004023:Dictyostelium / Q000235:genetics* / Q000254:growth & development; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins; D000242:Cyclic AMP