Sex and macrocyst formation in Dictyostelium

Abstract

Sex in Dictyostelia involves a remarkable form of cannibalism in which zygotes attract large numbers of surrounding amoebae and then ingest them. Before they are consumed, the attracted amoebae help the zygote by synthesising an outer wall around the aggregate that traps them inside and helps to protect the mature developed zygotic structure, the macrocyst. Competition between cells vying to contribute genetically to zygotes and through to the next generation seems likely to have promoted the evolution of several unusual features of dictyostelid sex: individual species often have more than two mating types, increasing haploid cells' chances of matching with a compatible partner, and fusion of many gametes to form transient syncytia allows cytoplasmic mixing and lateral transmission of mitochondrial genomes. This review will summarise recent advances in our understanding of mating-type determination, gamete fusion, and inheritance in Dictyostelium, and highlight the key gaps in our understanding of this fascinating set of phenomena.

Dictyostelium discoideum as a Model to Assess Genome Stability Through DNA Repair

“…In an alternative approach, genes encoding a small number of proteins implicated in DNA repair pathways in other eukaryotes are not apparent in the D. discoideum genome including ATM (Block and Lees-Miller, 2005;Hudson et al, 2005), a damage-activated protein kinase whose mutation in humans leads to Ataxia Telangiectasia. Similarly, D. discoideum undergoes a sexual life cycle with evidence for high levels of meiotic recombination but is missing an ortholog of Spo11, an enzyme required to initiate crossover during meiosis in other eukaryotes (Bloomfield, 2019;Bloomfield et al, 2019). Characterizing the molecular mechanisms which replace these "missing" components will reveal alternative pathways that might be exploited to ameliorate human diseases caused by their loss.…”

Autophagy of the somatic stalk cells likely nurses the propagating spores of Dictyostelid social amoebas

“…Unlike spores and cysts, macrocysts require long periods and as yet unknown stimuli to germinate. The latter property prohibited experimental studies, although progress was made in identification of genes required for macrocyst formation and genes that define the three mating types of Ddis ( Bloomfield, 2019 ; Urushihara & Muramoto, 2006 ). Macrocysts are common throughout the dictyostelid phylogeny ( Schaap et al , 2006 ) and their prolonged dormancy suggests a major role in long-term stress survival.…”

The WIPI Gene Family and Neurodegenerative Diseases: Insights From Yeast and Dictyostelium Models

“…Dictyostelium belongs to the amoebozoa group, and although this group of organisms diverged before the opistokonta (fungi and animals), it retains many features of animal cells that have been lost during the evolution of fungi. Cell motility and chemotaxis, phagocytosis and macropynocytosis are very similar to those observed in animal cells and Dictyostelium presents a multicellular stage that allows the study of cell differentiation and morphogenesis (see this series of reviews collected in a special issue dedicated to Dictyostelium in IJDB ( Araki and Saito, 2019 ; Batsios et al, 2019 ; Bloomfield, 2019 ; Bozzaro, 2019 ; Consalvo et al, 2019 ; Escalante and Cardenal-Muñoz, 2019 ; Farinholt et al, 2019 ; Fey et al, 2019 ; Fischer and Eichinger, 2019 ; Ishikawa-Ankerhold and Müller-Taubenberger, 2019 ; Jaiswal et al, 2019 ; Kawabe et al, 2019 ; Kay et al, 2019 ; Knecht et al, 2019 ; Kundert and Shaulsky, 2019 ; Kuspa and Shaulsky, 2019 ; Medina et al, 2019 ; Nanjundiah, 2019 ; Pal et al, 2019 ; Pearce et al, 2019 ; Pergolizzi et al, 2019 ; Schaf et al, 2019 ; Vines and King, 2019 ). Individual Dictyostelium cells ingest bacteria and yeasts in soil and the transition to a multicellular state, triggered when the food source is depleted, is accomplished by aggregation of preexisting cells.…”