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Integration of chemical-genetic & genetic interaction data links bioactive compounds to cellular target pathways Parsons et al. 2004 Nature Biotechnology Jed Shimizu Medical Genetics 505 March 31, 2005. The Goal:. Identifying targets of possible drugs. Gene A. Bioactive compound.
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Integration of chemical-genetic & genetic interaction data links bioactive compounds to cellular target pathways Parsons et al. 2004 Nature Biotechnology Jed Shimizu Medical Genetics 505 March 31, 2005
The Goal: Identifying targets of possible drugs Gene A Bioactive compound
The Method: • Using the S. cerevisiae deletion set • ~5000 non-essential genes in yeast • make up library of viable mutants Synthetic Lethality: Gene A Gene Y
The Method: • Using the S. cerevisiae deletion set • ~5000 non-essential genes in yeast • make up viable mutant set Synthetic Lethality: Gene Y deletion Alive
The Method: • Using the S. cerevisiae deletion set • ~5000 non-essential genes in yeast • make up viable mutant set Synthetic Lethality: Gene A deletion Alive Alive
The Method: • Using the S. cerevisiae deletion set • ~5000 non-essential genes in yeast • make up viable mutant set Synthetic Lethality: Alive Alive Genes A & Y deletion Dead
Synthetic Lethal Interaction Means… Dead • redundant function • interact with each other • mediate other’s function
Gene A? Screen Deletion Set with Drug of Interest Chemical-Genetic Interaction Profile
Back to Synthetic Lethality and the deletion set… Create collection of synthetic lethality profiles for possible drug target genes Genetic Interaction Profiles
Then Compare… …and find gene target of drug
Summary of Paper • Parsons et al. establish proof of concept: • chemical-genetic interaction profiles for 12 known inhibitory drugs • clean up noise in above profiles • genetic interaction profiles of possible gene targets • compare (1) and (3)
1. chemical-genetic interaction profiles Address Accuracy- Rapamycin Array contained 85 published rapamycin-sensitive strains Found 246 rapamycin-sensitive strains in total 39 of these among previously published Confirmed another 22 by spot assay
2. clean up the noise • Found genes with sensitivity to multiple drugs: • A multidrug-resistant • gene set • Included genes for: • ergosterol biosynthesis – membrane fluidity • vacuolar protein sorting • vacuolar H-ATPase complex
3. genetic interaction profiles- ERG11 example ERG11 Fluconazole
3. genetic interaction profiles- ERG11example Interaction profiles overlapped for 13 genes ERG11 genetic profile identified 14 genes Fluconazole profile identified 62 genes
3. genetic interaction profiles- ERG11example Interaction profiles overlapped for 11 genes ERG11 genetic profile identified 14 genes Fluconazole profile identified 35 genes
3. genetic interaction profiles - Significance ERG11 P = 3.8 X 10-56 P = 4.4 X 10-53 CNB1 P = 2.7 X 10-60
3. genetic interaction profiles – Why the Discrepancy? • Difference between chemical and genetic interactions • Genetic- no gene products • Chemical- act on gene product Drug Gene Y Dead Alive Gene Y associated to drug sensitivity due to interaction with drug, not drug target
4. comparison of interaction profiles • Focused on 6 Drugs • Compiled genetic interaction profiles for gene encoding drug target & related genes (57 in total) • Filtered multidrug-resistance set
4. comparison of interaction profiles – Bonus Info Provide info on uncharacterized genes: VID21- sensitive to camptothecin and hydroxyurea, possible role in DNA damage response
A Useful System to find Drug Targets? Chemical-Genetic Interaction Profile Genetic Interaction Profiles • get a lot of information • may work for certain drugs better • finding precise target difficult
Will become increasingly useful… • growing compendium of genetic profiles • groups already systematically compiling genetic interaction data using synthetic gene analysis in worms, flies, mammalian cell lines