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Updated: Aug 14, 2026
Biolistic Transformation of a Fluorescent Tagged Gene into the Opportunistic Fungal Pathogen Cryptococcus neoformans
Published on: March 19, 2015
Cryptococcus neoformans gene involved in mammalian pathogenesis identified by a Caenorhabditis elegans progeny-based
Robin J Tang1, Julia Breger, Alexander Idnurm
1Division of Infectious Diseases, Massachusetts General Hospital, Gray-Jackson 504, 55 Fruit Street, Boston, MA 02114, USA.
Abstract:
Caenorhabditis elegans can serve as a substitute host for the study of microbial pathogenesis. We found that mutations in genes of the fungal pathogen Cryptococcus neoformans involved in mammalian virulence allow C. elegans to produce greater numbers of progeny than when exposed to wild-type fungus. We used this property to screen a library of C. neoformans mutants for strains that permit larger C. elegans brood sizes. In this screen, we identified a gene homologous to Saccharomyces cerevisiae ROM2. C. neoformans rom2 mutation resulted in a defect in mating and growth defects at elevated temperature or in the presence of cell wall or hyperosmolar stresses. An effect of the C. neoformans rom2 mutation in virulence was confirmed in a murine inhalation infection model. We propose that a screen for progeny-permissive mutants of microorganisms can serve as a high-throughput method for identifying novel loci related to mammalian pathogenesis.
Insights
Using the nematode Caenorhabditis elegans as a model, researchers screened for Cryptococcus neoformans mutants that allow larger worm brood sizes. This identified a gene important for fungal virulence in mammals.
Area of Science:
- Microbiology
- Pathogenesis Research
- Model Organism Studies
Background:
- Caenorhabditis elegans is a valuable model for studying microbial pathogenesis.
- Investigating fungal virulence factors is crucial for understanding infectious diseases.
Purpose of the Study:
- To develop a high-throughput screening method for identifying microbial virulence genes.
- To identify novel Cryptococcus neoformans genes affecting pathogenesis using C. elegans.
Main Methods:
- Screening a library of Cryptococcus neoformans mutants based on C. elegans progeny size.
- Phenotypic characterization of identified mutants, including growth and virulence assays.
- Genetic analysis of the identified ROM2 gene homolog.
Main Results:
- Mutations in Cryptococcus neoformans virulence genes increased C. elegans brood size.
- A gene homologous to Saccharomyces cerevisiae ROM2 was identified as important for virulence.
- The C. neoformans rom2 mutant exhibited defects in mating, growth under stress, and reduced virulence in a murine model.
Conclusions:
- Screening for progeny-permissive microbial mutants in C. elegans is an effective high-throughput method for discovering virulence factors.
- The identified ROM2 gene homolog plays a significant role in Cryptococcus neoformans pathogenesis.
