RRC ID 31799
Author Kopecká M, Gabriel M, Takeo K, Yamaguchi M, Svoboda A, Ohkusu M, Hata K, Yoshida S.
Title Microtubules and actin cytoskeleton in Cryptococcus neoformans compared with ascomycetous budding and fission yeasts.
Journal Eur. J. Cell Biol.
Abstract Actin cytoskeleton and microtubules were studied in a human fungal pathogen, the basidiomycetous yeast Cryptococcus neoformans (haploid phase of Filobasidiella neoformans), during its asexual reproduction by budding using fluorescence and electron microscopy. Staining with rhodamine-conjugated phalloidin revealed an F-actin cytoskeleton consisting of cortical patches, cables and cytokinetic ring. F-actin patches accumulated at the regions of cell wall growth, i. e. in sterigma, bud and septum. In mother cells evenly distributed F-actin patches were joined to F-actin cables, which were directed to the growing sterigma and bud. Some F-actin cables were associated with the cell nucleus. The F-actin cytokinetic ring was located in the bud neck, where the septum originated. Antitubulin TAT1 antibody revealed a microtubular cytoskeleton consisting of cytoplasmic and spindle microtubules. In interphase cells cytoplasmic microtubules pointed to the growing sterigma and bud. As the nucleus was translocated to the bud for mitosis, the cytoplasmic microtubules disassembled and were replaced by a short intranuclear spindle. Astral microtubules then emanated from the spindle poles. Elongation of the mitotic spindle from bud to mother cell preceded nuclear division, followed by cytokinesis (septum formation in the bud neck). Electron microscopy of ultrathin sections of chemically fixed and freeze-substituted cells revealed filamentous bundles directed to the cell cortex. The bundles corresponded in width to the actin microfilament cables. At the bud neck numerous ribosomes accumulated before septum synthesis. We conclude: (i) the topology of F-actin patches, cables and rings in C. neoformans resembles ascomycetous budding yeast Saccharomyces, while the arrangement of interphase and mitotic microtubules resembles ascomycetous fission yeast Schizosaccharomyces. The organization of the cytoskeleton of the mitotic nucleus, however, is characteristic of basidiomycetous yeasts. (ii) A specific feature of C. neoformans was the formation of a cylindrical sterigma, characterized by invasion of F-actin cables and microtubules, followed by accumulation of F-actin patches around its terminal region resulting in development of an isodiametrical bud.
Volume 80(4)
Pages 303-11
Published 2001-4
DOI 10.1078/0171-9335-00157
PII S0171-9335(04)70145-4
PMID 11370745
MeSH Actin Cytoskeleton / ultrastructure* Cryptococcus neoformans / ultrastructure* Microscopy, Electron Microtubules / ultrastructure* Saccharomyces cerevisiae / ultrastructure Schizosaccharomyces / ultrastructure*
IF 3.024
Times Cited 37
Pathogenic microorganisms IFM 40042 IFM 41464 IFM 45842 IFM 45941