Uncovering genetic relationships using small molecules that selectively target yeast cell cycle mutants

Area of Science:

• * Molecular biology
• * Yeast genetics
• * Chemical biology

Background:

• * Budding yeast G1 cyclins (Cln1, Cln2) and cyclin-dependent kinases (Cdc28) regulate crucial cell cycle events, including entry, polarized growth, and spindle pole duplication.
• * Targeting these pathways offers potential for novel therapeutic strategies.

Purpose of the Study:

• * To develop a chemical genetic screen for identifying compounds targeting G1 cyclin pathways in yeast.
• * To discover novel small molecules selectively toxic to yeast lacking specific G1 cyclins.
• * To utilize these compounds in synthetic lethality screens to uncover new genetic interactions.

Main Methods:

• * Screening for compounds selectively toxic to a *cln1Δ cln2Δ* double mutant yeast strain.
• * Utilizing identified compounds (clinostatins) in a genome-wide chemical synthetic lethality screen.
• * Analyzing genetic interactions revealed by drug sensitivity in deletion mutant libraries.

Main Results:

• * Identification of a novel class of small molecules, termed 'clinostatins', highly toxic to *cln1Δ cln2Δ* yeast but not wild-type.
• * Discovery that components of the protein kinase C (PKC)-dependent MAP kinase pathway are sensitive to clinostatins.
• * Demonstration of clinostatin's utility in uncovering genetic interactions through chemical synthetic lethality.

Conclusions:

• * Clinostatins represent a promising tool for targeting G1 control pathways in yeast.
• * The combination of chemical synthetic lethality and chemical genomics screens is effective for identifying novel genetic interactions.
• * This approach has potential applications for uncovering conserved eukaryotic pathways.