Analysis of a genome-wide set of gene deletions in the fission yeast Schizosaccharomyces pombe

Abstract

Genome-wide single-gene deletion libraries can be important tools for understanding the molecular workings of an organism, but have only been created for a single eukaryotic species, Saccharomyces cerevisiae. Now, Kim et al. present a second collection of deletion mutants that covers 98.4% of the genes of Schizosaccharomyces pombe, allowing a systematic comparison of gene essentiality and knockout phenotypes between two eukaryotic species. We report the construction and analysis of 4,836 heterozygous diploid deletion mutants covering 98.4% of the fission yeast genome providing a tool for studying eukaryotic biology. Comprehensive gene dispensability comparisons with budding yeast—the only other eukaryote for which a comprehensive knockout library exists—revealed that 83% of single-copy orthologs in the two yeasts had conserved dispensability. Gene dispensability differed for certain pathways between the two yeasts, including mitochondrial translation and cell cycle checkpoint control. We show that fission yeast has more essential genes than budding yeast and that essential genes are more likely than nonessential genes to be present in a single copy, to be broadly conserved and to contain introns. Growth fitness analyses determined sets of haploinsufficient and haploproficient genes for fission yeast, and comparisons with budding yeast identified specific ribosomal proteins and RNA polymerase subunits, which may act more generally to regulate eukaryotic cell growth.