Plasmids from Staphylococcus aureus replicate in yeast Saccharomyces cerevisiae

Abstract

It is known that some plasmids, such as RP4, can replicate in many Gram-negative bacteria¹. Certain small Staphylococcus aureus plasmids have an even broader host range, being able to replicate in not only phylogenetically distant Gram-positive bacteria such as Bacillus subtilis² or Streptococcus pneumoniae³, but also in the Gram-negative bacterium Escherichia coli⁴. Here we have examined whether these plasmids can also replicate in a lower eukaryote, the yeast Saccharomyces cerevisiae. For this purpose we constructed hybrids between a S. aureus plasmid pC194 and an E. coli plasmid YIp5, which carries a ura-3 gene easy to select for in yeast but cannot replicate in this host. We found that the hybrids transformed yeast with high efficiency (as did hybrids between YIp5 and three other S. aureus plasmids); were maintained extrachromosomally in yeast; and were not modified during residence in yeast. We conclude from this evidence that S. aureus plasmids can replicate in yeast, which raises the questions of whether the replication signals used by prokaryotes and eukaryotes are similar, and how far up the phylogenetic tree the organisms still able to be hosts to S. aureus plasmids may be.