Deletion of many yeast introns reveals a minority of genes that require splicing for function

Mol Biol Cell. 2008 May;19(5):1932-41. doi: 10.1091/mbc.e07-12-1254. Epub 2008 Feb 20.


Splicing regulates gene expression and contributes to proteomic diversity in higher eukaryotes. However, in yeast only 283 of the 6000 genes contain introns and their impact on cell function is not clear. To assess the contribution of introns to cell function, we initiated large-scale intron deletions in yeast with the ultimate goal of creating an intron-free model eukaryote. We show that about one-third of yeast introns are not essential for growth. Only three intron deletions caused severe growth defects, but normal growth was restored in all cases by expressing the intronless mRNA from a heterologous promoter. Twenty percent of the intron deletions caused minor phenotypes under different growth conditions. Strikingly, the combined deletion of all introns from the 15 cytoskeleton-related genes did not affect growth or strain fitness. Together, our results show that although the presence of introns may optimize gene expression and provide benefit under stress, a majority of introns could be removed with minor consequences on growth under laboratory conditions, supporting the view that many introns could be phased out of Saccharomyces cerevisiae without blocking cell growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cytoskeleton / genetics
  • Deoxyribonucleases, Type II Site-Specific / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation, Fungal
  • Genes, Fungal*
  • Introns / genetics*
  • Phenotype
  • Promoter Regions, Genetic / genetics
  • RNA Splicing / genetics*
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae Proteins / genetics
  • Selection, Genetic
  • Sequence Deletion*


  • Saccharomyces cerevisiae Proteins
  • SCEI protein, S cerevisiae
  • Deoxyribonucleases, Type II Site-Specific