Related Experiment Videos
Development of pseudohyphae by embedded haploid and diploid yeast
W S Lo1, E I Raitses, A M Dranginis
1Department of Biological Sciences, St. John's University, Jamaica, New York 11439, USA.
Current Genetics
|October 27, 1997
Summary
Yeast, including haploid and diploid Saccharomyces cerevisiae, form filamentous pseudohyphae when embedded in agar, independent of nutrient starvation. This process utilizes the STE12 pathway, distinct from the nitrogen starvation response.
Area of Science:
- Cell Biology
- Microbiology
- Genetics
Background:
- Diploid Saccharomyces cerevisiae (yeast) strains are known to form pseudohyphae under nitrogen starvation conditions.
- Pseudohyphae are elongated yeast cells that remain attached, forming filamentous structures.
- The genetic regulation of pseudohyphae formation, particularly in response to different stimuli, is an area of ongoing research.
Purpose of the Study:
- To investigate yeast filamentous growth in conditions other than nitrogen starvation.
- To determine if haploid and diploid yeast exhibit filamentous growth when embedded within solid media.
- To elucidate the genetic pathways and regulatory elements involved in embedded yeast filamentous growth.
Main Methods:
- Culturing haploid and diploid Saccharomyces cerevisiae strains in solid agar media.
- Observing and characterizing filamentous growth (pseudohyphae) in embedded yeast cells.
- Utilizing gene deletion mutants (e.g., BUD5, STE12, a1/alpha 2 repressor) to assess genetic requirements for filamentation.
Main Results:
- Both haploid and diploid yeast form pseudohyphae when embedded in solid media, irrespective of nutrient availability (rich media).
- Pseudohyphae formation in embedded cells is independent of the a1/alpha 2 repressor, which is crucial for nitrogen starvation-induced filamentation.
- Deletion of BUD5 impairs pseudohyphae formation in embedded cells, indicating ordered filament formation.
- Deletion of STE12 abolishes pseudohyphae formation in all tested conditions, highlighting its essential role in the shared signal transduction pathway.
Conclusions:
- Saccharomyces cerevisiae exhibits distinct mechanisms for pseudohyphae formation, responding to both nutrient starvation and physical embedding in solid media.
- The STE12-mediated signal transduction pathway is conserved and essential for filamentous growth across different environmental stimuli.
- Yeast cell type (haploid/diploid) and specific genetic elements (e.g., a1/alpha 2 repressor, BUD5) differentially regulate filamentation responses.