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Updated: Apr 1, 2026
07:40
Identification of Host Pathways Targeted by Bacterial Effector Proteins using Yeast Toxicity and Suppressor Screens
Published on: October 25, 2019
6.5K
Summary
The NIB gene mutation in Saccharomyces cerevisiae causes abnormal cell growth and colony morphology due to increased 2-micron DNA copy number. This defect in DNA replication regulation leads to larger cells and mortal clones.
Area of Science:
- Yeast genetics
- Molecular biology
- Cellular regulation
Background:
- Saccharomyces cerevisiae strains with the nib allele and 2-micron DNA exhibit a
- nibbled
- colony morphology.
- This phenotype is linked to a subpopulation of abnormally large cells.
Purpose of the Study:
- Investigate the cause of the nibbled colony phenotype.
- Determine the relationship between cell size, 2-micron DNA copy number, and the NIB allele.
- Elucidate the function of the NIB gene.
Main Methods:
- Phenotypic analysis of yeast colonies.
- Cell size determination.
- Quantification of 2-micron DNA copy number.
Main Results:
- The nibbled phenotype correlates with large cells resulting from DNA replication or nuclear division defects.
- Large nib cells have double the 2-micron DNA copy number compared to small cells.
- Elevated 2-micron DNA copy number causes increased cell size.
Conclusions:
- The NIB gene product normally represses 2-micron DNA amplification.
- The nib allele is partially defective, leading to uncontrolled 2-micron DNA copy number increase and the nibbled phenotype.
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