Open AccessMarker Removal in Staphylococci via Cre Recombinase and Different lox Sites
Author(s) -
Martina Leibig,
Bernhard Krismer,
Martina Kolb,
Alexandra Friede,
Friedrich Götz,
Ralph Bertram
Publication year - 2008
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.02424-07
Subject(s) - plasmid , recombinase , biology , genetics , gene , site specific recombination , transformation (genetics) , mutant , operon , cre recombinase , transposable element , kanamycin , genome , cre lox recombination , origin of replication , recombination , transgene , genetically modified mouse
Allelic replacement in staphylococci is frequently aided by antibiotic resistance markers that replace the gene(s) of interest. In multiply modified strains, the number of mutated genes usually correlates with the number of selection markers in the strain's chromosome. Site-specific recombination systems are capable of eliminating such markers, if they are flanked by recombinase recognition sites. In this study, a Cre-lox setting was established that allowed the efficient removal of resistance genes from the genomes ofStaphylococcus carnosus andS. aureus . Two cassettes conferring resistance to erythromycin or kanamycin were flanked with wild-type or mutantlox sites, respectively, and used to delete single genes and an entire operon. After transformation of the cells with a newly constructedcre expression plasmid (pRAB1), genomic eviction of the resistance genes was observed in approximately one out of ten candidates analyzed and subsequently verified by PCR. Due to its thermosensitive origin of replication, the plasmid was then easily eliminated at nonpermissive temperatures. We anticipate that the system presented here will prove useful for generating markerless deletion mutants in staphylococci.