Grant: Canada Research Chairs

The most deeply evolutionarily conserved human genes encode essential cellular machinery whose failures are linked to diverse diseases in humans. Many systematic studies have discovered extensive genetic polymorphism in these genes. Yet studying how these variations contribute to cellular function and overall human health remains a challenge. Our research studies these conserved human genes and many of their variants by systematically humanizing yeast cells, replacing each essential yeast gene with its human version. The resulting yeast strains serve as biological test tubes for studying the human genes in a simplified organismal context, opening up simple high-throughput assays of human gene function, analyzing the impact of human genetic variation on gene function, the screening and repurposing of drugs and the rapid determination of mechanisms of drug resistance. The proposed studies also illuminate fundamental principles of evolution, providing direct measurements of whether human and yeast genes have retained their ancestral functions over a billion years of evolutionary divergence. The following aims describe our broad research interests in the laboratory: I. Generate humanized-yeast avatars relevant to human disease. The project explores engineering complex human biological processes in yeast by performing single to multiple human gene swaps in yeast, focusing on the proteasome complex and sterol biosynthesis pathway. II. Personalize the humanized-yeast to screen for loss-of-function and hypomorphic human gene alleles in yeast. By swapping essential yeast genes with human counterparts, we would have coupled the fitness of that human gene with the fitness of the yeast cell. Therefore, mutations with functional consequences will show phenotypic differences in the humanized-yeast and simple growth assays serve as an easily measured proxy for the proper functioning of the human gene. III. Genome-wide CRISPR-CAS9-gRNA libraries, modular toolkits, and novel technologies for high throughput genome editing in yeasts. Our laboratory tests the humanization of many genes at scale, thus, generating precious, multiplex genome editing resources and novel toolkits. Our research proposes the most extensive, rigorous, and systematic test of humanization ever performed. The resulting toolkits, CRISPR libraries and humanized yeast strains are freely distributed upon request. IV. Humanize yeast exosomes or extra-cellular vesicles for therapeutic purposes.