An RNA Transport System in Candida albicans Regulates Hyphal Morphology and Invasive Growth

Fred Hutchinson Cancer Research Center, United States of America
PLoS Genetics (Impact Factor: 7.53). 09/2009; 5(9):e1000664. DOI: 10.1371/journal.pgen.1000664
Source: PubMed


Author Summary
Generation of cellular polarity – asymmetry in shape, protein distribution, and/or sub-cellular function – is an essential feature of most eukaryotic cells and underlies such diverse processes as differentiation, mating, nutrient acquisition, and growth. Localization of specific mRNAs is one mechanism through which cells achieve polarity. We describe an RNA transport system in Candida albicans, a fungal pathogen of humans, that grows in both single cell (budding yeast) and filamentous (hyphal and pseudohyphal) forms. Hyphae are chains of elongated cells that remain attached after cell division and exhibit highly polarized growth at their tips. We show that the C. albicans She3-dependent RNA transport system binds to 40 mRNAs and transports these mRNAs to yeast buds and to the tips of hyphae. Both the transport system itself and many of the genes encoded by transported mRNAs are required for normal growth and function of hyphae. Although the basic transport mechanism appears conserved with that of the model yeast, Saccharomyces cerevisiae, the cargo mRNAs are largely distinct. The apparently rapid evolution of the transported mRNAs probably reflects distinct selective pressures acting on the two organisms.

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    • "On SLAD agar the hsp21Δ/Δ mutant formed aberrant colonies which completely lacked the peripheral filaments observed for the wild type. When grown on Spider agar the wild type typically forms colonies with a central wrinkled area consisting of yeast, hyphae and pseudohyphae and a peripheral area consisting mainly of agar-invading filaments [77]. In contrast, the hsp21Δ/Δ mutant developed wrinkled colonies that completely lacked peripheral hyphae. "
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    • "In distant fungal species such as Candida albicans, a She3p homolog but not a She2p homolog is present in the genome [72]. As in S.cerevisiae, ASH1 mRNA in C. albicans is transported in a She3p-dependent manner [72]. "
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    ABSTRACT: mRNA localization and localized translation is a common mechanism by which cellular asymmetry is achieved. In higher eukaryotes the mRNA transport machinery is required for such diverse processes as stem cell division and neuronal plasticity. Because mRNA localization in metazoans is highly complex, studies at the molecular level have proven to be cumbersome. However, active mRNA transport has also been reported in fungi including Saccharomyces cerevisiae, Ustilago maydis and Candida albicans, in which these events are less difficult to study. Amongst them, budding yeast S. cerevisiae has yielded mechanistic insights that exceed our understanding of other mRNA localization events to date. In contrast to most reviews, we refrain here from summarizing mRNA localization events from different organisms. Instead we give an in-depth account of ASH1 mRNA localization in budding yeast. This approach is particularly suited to providing a more holistic view of the interconnection between the individual steps of mRNA localization, from transcriptional events to cytoplasmic mRNA transport and localized translation. Because of our advanced mechanistic understanding of mRNA localization in yeast, the present review may also be informative for scientists working, for example, on mRNA localization in embryogenesis or in neurons.
    Full-text · Article · Dec 2011 · Cellular and Molecular Life Sciences CMLS
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    • "A high rate of RNA decay of transcripts involved in regulatory systems has been reported in S. cerevisiae as well [34]. Intriguingly, of the 38 RNAs identified recently as She3-transported in C. albicans during hyphal growth [35], 9 were found to exhibit long 5' UTRs (P = 4.3e-04). This leads us to speculate that long 5' UTRs are probably required for RNA transport to cellular locations where hyphal buds are produced. "
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