Cycloheximide-resistant temperature-sensitive lethal mutations of Saccharomyces cerevisiae

Area of Science:

• Molecular biology
• Yeast genetics
• Cell cycle regulation

Background:

• Cycloheximide resistance and temperature-sensitive (ts) mutations are valuable tools for studying essential genes.
• Identifying novel mutations aids in understanding fundamental cellular processes.

Purpose of the Study:

• To isolate and characterize new pleiotropic mutations conferring cycloheximide resistance and temperature-sensitive growth.
• To identify novel genes involved in yeast cell cycle progression and stress response.

Main Methods:

• Screening for cycloheximide-resistant, temperature-sensitive lethal (crl) mutants in yeast.
• Complementation analysis to establish 22 distinct complementation groups.
• Genetic mapping of 15 CRL loci.
• Phenotypic analysis at non-permissive (37°C) and low (5°C) temperatures.
• Analysis of extragenic suppressor mutations.

Main Results:

• Isolation of 22 complementation groups of novel crl mutations.
• Mutants arrest late in the cell cycle at 37°C after multiple divisions.
• Approximately half of the mutants show cold-sensitive growth at 5°C.
• Specific suppressor mutations partially or fully restored growth for subsets of crl mutants, indicating distinct genetic interactions.

Conclusions:

• The identified crl mutations represent novel genes essential for yeast cell viability and cell cycle progression.
• The diverse phenotypes suggest involvement of these genes in multiple cellular pathways.
• Further characterization of these CRL loci will elucidate new aspects of cell cycle control and stress response in eukaryotes.