| Title: | A systematic screen for morphological abnormalities during fission yeast sexual reproduction identifies a mechanism of actin aster formation for cell fusion |
| Author(s): | Dudin O; Merlini L; Bendezu FO; Groux R; Vincenzetti V; Martin SG; |
| Address: | "Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland" |
| DOI: | 10.1371/journal.pgen.1006721 |
| ISSN/ISBN: | 1553-7404 (Electronic) 1553-7390 (Print) 1553-7390 (Linking) |
| Abstract: | "In non-motile fungi, sexual reproduction relies on strong morphogenetic changes in response to pheromone signaling. We report here on a systematic screen for morphological abnormalities of the mating process in fission yeast Schizosaccharomyces pombe. We derived a homothallic (self-fertile) collection of viable deletions, which, upon visual screening, revealed a plethora of phenotypes affecting all stages of the mating process, including cell polarization, cell fusion and sporulation. Cell fusion relies on the formation of the fusion focus, an aster-like F-actin structure that is marked by strong local accumulation of the myosin V Myo52, which concentrates secretion at the fusion site. A secondary screen for fusion-defective mutants identified the myosin V Myo51-associated coiled-coil proteins Rng8 and Rng9 as critical for the coalescence of the fusion focus. Indeed, rng8Delta and rng9Delta mutant cells exhibit multiple stable dots at the cell-cell contact site, instead of the single focus observed in wildtype. Rng8 and Rng9 accumulate on the fusion focus, dependent on Myo51 and tropomyosin Cdc8. A tropomyosin mutant allele, which compromises Rng8/9 localization but not actin binding, similarly leads to multiple stable dots instead of a single focus. By contrast, myo51 deletion does not strongly affect fusion focus coalescence. We propose that focusing of the actin filaments in the fusion aster primarily relies on Rng8/9-dependent cross-linking of tropomyosin-actin filaments" |
| Keywords: | Actin Cytoskeleton/genetics/metabolism Actins/genetics Amino Acid Sequence/genetics Cell Cycle Proteins/*genetics Cytoskeleton/genetics/metabolism Myosin Type V/*genetics/metabolism Myosins/*genetics Phenotype Protein Binding Reproduction/genetics Schizos; |
| Notes: | "MedlineDudin, Omaya Merlini, Laura Bendezu, Felipe O Groux, Raphael Vincenzetti, Vincent Martin, Sophie G eng 2017/04/15 PLoS Genet. 2017 Apr 14; 13(4):e1006721. doi: 10.1371/journal.pgen.1006721. eCollection 2017 Apr" |
