RT Journal Article SR Electronic(1) A1 Janis, Carole A1 Bischof, Daniela A1 Gourgues, Géraldine A1 Frey, Joachim A1 Blanchard, Alain A1 Sirand-Pugnet, PascalYR 2008 T1 Unmarked insertional mutagenesis in the bovine pathogen Mycoplasma mycoides subsp. mycoides SC: characterization of a lppQ mutant JF Microbiology, VO 154 IS 8 SP 2427 OP 2436 DO https://doi.org/10.1099/mic.0.2008/017640-0 PB Microbiology Society, SN 1465-2080, AB Mycoplasma mycoides subspecies mycoides small colony (SC) is the aetiologic agent of contagious bovine pleuropneumonia (CBPP), a respiratory disease causing important losses in cattle production. The publication of the genome sequence of M. mycoides subsp. mycoides SC should facilitate the identification of putative virulence factors. However, real progress in the study of molecular mechanisms of pathogenicity also requires efficient molecular tools for gene inactivation. In the present study, we have developed a transposon-based approach for the random mutagenesis of M. mycoides subsp. mycoides SC. A PCR-based screening assay enabled the characterization of several mutants with knockouts of genes potentially involved in pathogenicity. The initial transposon was further improved by combining it with the transposon γδ TnpR/res recombination system to allow the production of unmarked mutations. Using this approach, we isolated a mutant free of antibiotic-resistance genes, in which the gene encoding the main lipoprotein LppQ was disrupted. The mutant was found to express only residual amounts of the truncated N-terminal end of LppQ. This approach opens the way to study virulence factors and pathogen–host interactions of M. mycoides subsp. mycoides SC and to develop new, genetically defined vaccine strains., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.2008/017640-0