The ClosTron: a universal gene knock-out system for the genus Clostridium.
Progress in exploiting clostridial genome information has been severely impeded by a general lack of effective methods for the directed inactivation of specific genes. Those few mutants that have been generated have been almost exclusively derived by single crossover integration of a replication-deficient or defective plasmid by homologous recombination. The mutants created are therefore unstable. Here we have adapted a mutagenesis system based on the mobile group II intron from the ltrB gene of Lactococcus lactis (Ll.ltrB) to function in clostridial hosts. Integrants are readily selected on the basis of acquisition of resistance to erythromycin, and are generated from start to finish in as little as 10 to 14 days. Unlike single crossover plasmid integrants, the mutants are extremely stable. The system has been used to make 6 mutants of Clostridium acetobutylicum and 5 of Clostridium difficile, exceeding the number of published mutants ever generated in these species. Genes have also been inactivated for the first time in Clostridium botulinum and Clostridium sporogenes, suggesting the system will be universally applicable to the genus. The procedure is highly efficient and reproducible, and should revolutionize functional genomic studies in clostridia.
Institute of Infection, Immunity and Inflammation, School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
John T
JT
Heap
Oliver J
OJ
Pennington
Stephen T
ST
Cartman
Glen P
GP
Carter
Nigel P
NP
Minton
D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003013:Clostridium / Q000235:genetics*; D003227:Conjugation, Genetic / Q000235:genetics; D017353:Gene Deletion; D007438:Introns; D007544:Isopropyl Thiogalactoside / Q000235:genetics; D013294:Lactococcus lactis / Q000235:genetics; D016254:Mutagenesis, Insertional / Q000235:genetics* / Q000379:methods; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D012194:RNA-Directed DNA Polymerase / Q000235:genetics; D011995:Recombination, Genetic; D018626:Retroelements / Q000235:genetics
D001426:Bacterial Proteins; D018626:Retroelements; D007544:Isopropyl Thiogalactoside; C099785:LtrA protein, Lactococcus lactis; D012194:RNA-Directed DNA Polymerase