Construction and analysis of chromosomal Clostridium difficile mutants.
Clostridium difficile is an emerging nosocomial pathogen of increasing importance and virulence but our ability to study the molecular mechanisms underlying the pathogenesis of C. difficile-associated disease has been limited because of a lack of tools for its genetic manipulation. We have now developed a reproducible method for the targeted insertional inactivation of chromosomal C. difficile genes. The approach relies on the observation that an Escherichia coli-Clostridium perfringens shuttle vector is unstable in C. difficile and can be used as a form of conditional lethal vector to deliver gene constructs to the chromosome. We have used this methodology to insertionally inactivate two putative response regulator genes, rgaR and rgbR, which encode proteins with similarity to the toxin gene regulator, VirR, from C. perfringens. Transcriptomic analysis demonstrated that the C. difficile RgaR protein positively regulated four genes, including a putative agrBD operon. The RgaR protein was also purified and shown to bind specifically to sites that contained two consensus VirR boxes located just upstream of the putative promoters of these genes. The development of this methodology will significantly enhance our ability to use molecular approaches to develop a greater understanding of the ability of C. difficile to cause disease.
O'Connor
Jennifer R
JR
Australian Bacterial Pathogenesis Program, Department of Microbiology, Monash University, Vic. 3800, Australia.
Lyras
Dena
D
Farrow
Kylie A
KA
Adams
Vicki
V
Powell
David R
DR
Hinds
Jason
J
Cheung
Jackie K
JK
Rood
Julian I
JI
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002876:Chromosomes, Bacterial / Q000235:genetics*; D016360:Clostridioides difficile / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D005816:Genetic Complementation Test; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000379:methods; D009154:Mutation / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins