Temporal and Spatial Differences in Cell Wall Expansion during Bud and Mycelium Formation in Candida albicans

Staebell, Margaret; Soll, David R.

doi:10.1099/00221287-131-6-1467

Cited by 47 publications

(56 citation statements)

References 22 publications

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“…This apical growth zone is active during the entire hyphal growth period (Staebell and Soll, 1985). In contrast, yeast-form cells expand from a small area in a mostly apical manner only at the initial stage of budding.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, yeast-form cells expand from a small area in a mostly apical manner only at the initial stage of budding. When the bud has reached a critical size, apical growth shuts down and general (isotropic) expansion takes place (Staebell and Soll, 1985). The localization of the actin cytoskeleton in yeast and hyphal cells reflects these differences in morphogenesis.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hyphal Elongation Is Regulated Independently of Cell Cycle inCandida albicans

Hazan

Sepulveda-Becerra

Liu

2002

MBoC

105

138

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The mechanism for apical growth during hyphal morphogenesis in Candida albicans is unknown. Studies from Saccharomyces cerevisiae indicate that cell morphogenesis may involve cell cycle regulation by cyclin-dependent kinase. To examine whether this is the mechanism for hyphal morphogenesis, the temporal appearance of different spindle pole body and spindle structures, the cell cycle-regulated rearrangements of the actin cytoskeleton, and the phosphorylation state of the conserved Tyr19 of Cdc28 during the cell cycle were compared and found to be similar between yeast and serum-induced hyphal apical cells. These data suggest that hyphal elongation is not mediated by altering cell cycle progression or through phosphorylation of Tyr19 of Cdc28. We have also shown that germ tubes can evaginate before spindle pole body duplication, chitin ring formation, and DNA replication. Similarly, tip-associated actin polarization in each hypha occurs before the events of the G 1 /S transition and persists throughout the cell cycle, whereas cell cycle-regulated actin assemblies come and go. We have also shown that cells in phases other than G 1 can be induced to form hyphae. Hyphae induced from G 1 cells have no constrictions, and the first chitin ring is positioned in the germ tube at various distances from the base. Hyphae induced from budded cells have a constriction and a chitin ring at the bud neck, beyond which the hyphae continue to elongate with no further constrictions. Our data suggest that hyphal elongation and cell cycle morphogenesis programs are uncoupled, and each contributes to different aspects of cell morphogenesis. INTRODUCTIONCandida albicans is a polymorphic fungal pathogen that undergoes reversible morphogenetic transitions among budding, pseudohyphal, and hyphal growth forms (Odds, 1985). Its ability to switch between yeast and hyphal growth forms is directly related to its virulence, because mutants defective in hyphal growth are less virulent in mouse models than are their wild-type counterparts (Leberer et al., 1997;Lo et al., 1997;Gale et al., 1998). Hyphae may be suited to breach barriers in the host, whereas the yeast form is more easily disseminated within the host. Therefore, understanding the mechanisms for this morphogenetic switch should provide insight into the pathogenicity of this fungus.During hyphal growth in C. albicans, cell surface expansion is restricted to a small region at the hyphal tip. This apical growth zone is active during the entire hyphal growth period (Staebell and Soll, 1985). In contrast, yeast-form cells expand from a small area in a mostly apical manner only at the initial stage of budding. When the bud has reached a critical size, apical growth shuts down and general (isotropic) expansion takes place (Staebell and Soll, 1985). The localization of the actin cytoskeleton in yeast and hyphal cells reflects these differences in morphogenesis. Polarization of the actin cytoskeleton to the hyphal tip is observed in all hyphal cells (Anderson and Soll, 1986). However, in yeast-...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hyphal Elongation Is Regulated Independently of Cell Cycle inCandida albicans

Hazan

Sepulveda-Becerra

Liu

2002

MBoC

105

138

View full text Add to dashboard Cite

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“…During yeast growth, cells proliferate by budding, and polarized growth occurs at distinct sites in different stages of the cell cycle (Anderson and Soll, 1986). By contrast, cell growth in true hyphal cells occurs in a cell cycle-independent manner, being persistently confined to hyphal tips (Staebell and Soll, 1985;Anderson and Soll, 1986;Zheng et al, 2003;Zheng et al, 2004). It has been shown that actin cortical patches and cables polarize towards hyphal tips throughout hyphal growth Zheng et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

The formin family protein CaBni1p has a role in cell polarity control during both yeast and hyphal growth inCandida albicans

Wang

Zheng

et al. 2005

Journal of Cell Science

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Formins are conserved eukaryotic proteins playing key roles in regulating cell polarity. We have characterized the roles of a formin CaBni1p in the polymorphic fungus Candida albicans. CaBni1p localized persistently to hyphal tips during hyphal growth but to distinct growth sites at different cell cycle stages during yeast growth. Cabni1Δ yeast cells exhibited several morphological defects, such as round and enlarged cells, widened bud necks and a random budding pattern. Although Cabni1Δ cells could still undergo yeast-hypha growth switch, the hyphae were markedly swollen. Cabni1Δ also showed defects in spindle and cytoplasmic microtubule orientation and positioning. Coincidentally, the spindle orientation protein CaKar9p in Cabni1Δ yeast cells appeared as multiple random cortical spots, in contrast to the single spot at the bud tip of many wild-type cells. Interestingly, several defects manifested in Cabni1Δ yeast cells were partially corrected during hyphal growth. We found that the second formin CaBnr1p was recruited to hyphal tips, while it localized only to the bud neck during yeast growth. This behavior of CaBnr1p may play a key role in correcting Cabni1Δ defects during hyphal growth. Cabni1Δ exhibited reduced virulence in mice. These results indicate that the formins play an important role in Candida albicans polarized growth and CaBni1p's function is required for virulence.

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“…The switch from yeast to hyphal growth represents a transition to a more polarized form of growth since budding occurs predominantly by isotropic wall expansion while germ tube growth is confined mainly to the apex (Staebell & Soll, 1985). We show that both yeast and hyphal forms are polarized by the electrical fields but that the fields do not induce the yeast-hyphal transition.…”

Section: Introductionmentioning

confidence: 79%

“…The electrical field effects again seem to be directed rather specifically to the processes that affect the directional growth of the cell. It is of interest that electrical fields did not lead to the conversion of growth by budding to germ tube growth despite the fact that the germ tube can be regarded as being a highly polarized bud (Staebell & Soll, 1985 ;Gow, 1988). Chaffin (1984) showed that buds of C. albicans were often formed adjacent to one another for cells grown at 23-28 "C while site selection was non-adjacent for germ tubes or for buds produced at 37 "C. Our results demonstrate that site selection mechanisms can be made to generate adjacent evaginations for both buds and germ tubes.…”

Section: Discussionmentioning

confidence: 99%

Influence of applied electrical fields on yeast and hyphal growth of Candida albicans

Crombie

Gow

Gooday

1990

Journal of General Microbiology

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Yeast cells of Candida dbicans which had been attached to polylysine-coated microscope slides were induced to form buds or germ tubes in the presence of external electrical fields. The sites of budding and germ tube formation and the growth of germ tubes and hyphal branches were polarized preferentially towards the cathode. Buds were not converted to pseudohyphae or germ tubes by the field and the field had no effect on the positioning of nuclei or septa in the yeast cell or germ tube. Buds were less polarized than germ tubes at any given applied voltage. The polarization of buds reached a peak at an electrical field of 12 mV per cell. Polarization of germ tubes was biphasic, incri5adihgrapidly with %cre*&hig field strengths up to 5 mV per cell, and then more slowly in stronger fields. An electrical field was only required for a fraction of the time taken for germ tubes to start to form, so cells retained a memory of experiencing an electrical field which influenced the selection of sites of evagination. Increasing the electrical field delayed the time of germ tube evagination and inhibited the rate of germ tube extension. Unlike previous findings with other filamentous fungi, germ tubes grew unidirectionally towards the cathode for extended periods and did not deviate to a perpendicular orientation. This result suggests that the septa1 pore of the filamentous form may have high electrical resistance and would act as an effective barrier to solute transport between intercalary compartments.

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Temporal and Spatial Differences in Cell Wall Expansion during Bud and Mycelium Formation in Candida albicans

Cited by 47 publications

References 22 publications

Hyphal Elongation Is Regulated Independently of Cell Cycle inCandida albicans

Hyphal Elongation Is Regulated Independently of Cell Cycle inCandida albicans

The formin family protein CaBni1p has a role in cell polarity control during both yeast and hyphal growth inCandida albicans

Influence of applied electrical fields on yeast and hyphal growth of Candida albicans

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