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Chitin synthetase mutants of Phycomyces blakesleeanus
B Cubero1, J Ruiz-Herrera, E Cerdá-Olmedo
1Departamento de Genética, Universidad de Sevilla, Spain.
Molecular & General Genetics : MGG
|July 1, 1993
Summary
Researchers identified a gene, chsA, responsible for nikkomycin resistance in Phycomyces blakesleeanus. This gene is crucial for chitin biosynthesis, impacting fungal growth and drug sensitivity.
Area of Science:
- Mycology
- Biochemistry
- Genetics
Background:
- Nikkomycin is a potent inhibitor of chitin biosynthesis.
- Chitin is a vital component of fungal cell walls.
- Understanding chitin synthesis is key to developing antifungal strategies.
Purpose of the Study:
- To isolate and characterize mutants of Phycomyces blakesleeanus resistant to nikkomycin.
- To identify the genetic basis of nikkomycin resistance.
- To elucidate the role of the identified gene in chitin biosynthesis.
Main Methods:
- Chemical mutagenesis of wild-type Phycomyces blakesleeanus spores using N-methyl-N'-nitro-N-nitrosoguanidine.
- Genetic analysis to map resistance mutations.
- Phenotypic characterization of mutants and wild type in the presence and absence of nikkomycin.
- In vivo and in vitro assays of chitin synthesis kinetics.
Main Results:
- Nikkomycin-resistant mutants were successfully isolated.
- Resistance was mapped to a single gene, designated chsA.
- chsA mutants exhibited significantly reduced sensitivity to nikkomycin compared to wild type.
- Mutations in chsA altered the allosteric regulation and nikkomycin inhibition of chitin synthetase.
Conclusions:
- The chsA gene is essential for chitin biosynthesis in Phycomyces blakesleeanus.
- chsA encodes chitin synthetase or a critical subunit thereof.
- The study provides insights into the structure and function of chitin synthetase and its regulation.