Extending the Schizosaccharomyces pombe molecular genetic toolbox

PLoS One. 2014 May 21;9(5):e97683. doi: 10.1371/journal.pone.0097683. eCollection 2014.

Abstract

Targeted alteration of the genome lies at the heart of the exploitation of S. pombe as a model system. The rate of analysis is often determined by the efficiency with which a target locus can be manipulated. For most loci this is not a problem, however for some loci, such as fin1+, rates of gene targeting below 5% can limit the scope and scale of manipulations that are feasible within a reasonable time frame. We now describe a simple modification of transformation procedure for directing integration of genomic sequences that leads to a 5-fold increase in the transformation efficiency when antibiotic based dominant selection markers are used. We also show that removal of the pku70+ and pku80+ genes, which encode DNA end binding proteins required for the non-homologous end joining DNA repair pathway, increases the efficiency of gene targeting at fin1+ to around 75-80% (a 16-fold increase). We describe how a natMX6/rpl42+ cassette can be used for positive and negative selection for integration at a targeted locus. To facilitate the evaluation of the impact of a series of mutations on the function of a gene of interest we have generated three vector series that rely upon different selectable markers to direct the expression of tagged/untagged molecules from distinct genomic integration sites. pINTL and pINTK vectors use ura4+ selection to direct disruptive integration of leu1+ and lys1+ respectively, while pINTH vectors exploit nourseothricin resistance to detect the targeted disruption of a hygromycin B resistance conferring hphMX6 cassette that has been integrated on chromosome III. Finally, we have generated a series of multi-copy expression vectors that use resistance to nourseothricin or kanamycin/G418 to select for propagation in prototrophic hosts. Collectively these protocol modifications and vectors extend the versatility of this key model system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Drug Resistance, Bacterial / genetics
  • Genetic Engineering / methods*
  • Genetic Vectors / genetics
  • Genome, Bacterial / genetics
  • Schizosaccharomyces / drug effects
  • Schizosaccharomyces / genetics*
  • Sequence Homology, Nucleic Acid
  • Streptothricins / pharmacology
  • Transformation, Genetic

Substances

  • Anti-Bacterial Agents
  • Streptothricins