A genome-wide nanotoxicology screen of Saccharomyces cerevisiae mutants reveals the basis for cadmium sulphide quantum dot tolerance and sensitivity

Abstract

The use of cadmium sulphide quantum dots (CdS QDs) is increasing, particularly in the electronics industry. Their size (1–10 nm in diameter) is, however, such that they can be taken up by living cells. Here, a bakers’ yeast (Saccharomyces cerevisiae) deletion mutant collection has been exploited to provide a high-throughput means of revealing the genetic basis for tolerance/susceptibility to CdS QD exposure. The deletion of 112 genes, some associated with the abiotic stress response, some with various metabolic processes, some with mitochondrial organization, some with transport and some with DNA repair, reduced the level of tolerance to CdS QDs. A gene ontology analysis highlighted the role of oxidative stress in determining the cellular response. The transformation of sensitive mutants with centromeric plasmids harbouring DNA from a wild type strain restored the wild type growth phenotype when the complemented genes encoded either HSC82, DSK2 or ALD3. The use of these simple eukaryote knock-out mutants for functional toxicogenomic analysis will inform studies focusing on higher organisms.

• Barcode yeast mutants
• functional toxicology
• gene ontology analysis
• genetic complementation
• yeast transformation

Acknowledgements

The authors thank Prof. Salvatore Iannotta from IMEM-CNR (Parma) for his support and Prof. Mauro Giacca from ICGEB (Trieste) for making available the facilities required for yeast transformation. The authors also thank Dr. Robert Koebner for thoroughly reading and helping in editing the manuscript.

Declaration of interest

This research was financially supported by the Italian Ministry of Research under grant PRIN 2008-XS9YBC_002 and by the EUROTRANS-BIO project “Preparation, validation and commercialization of prototype toxigenomics chip” (TOXICHIP). The authors declare no conflict of interest. The authors alone are responsible for the content and writing of the paper.

Supplementary material available online

Supplementary Tables S1-S11 and Figures S1-S4.