The complete genome sequence of the murine respiratory pathogen Mycoplasmapulmonis

Mycoplasma pulmonis is a wall-less eubacterium belonging to the Mollicutes (trivial name, mycoplasmas) and responsible for murine respiratory diseases . The genome of strain UAB CTIP is composed of a single circular 963 879 bp chromosome with a G + C content of 26.6 mol%, i.e. the lowest reported amo ng bacteria, Ureaplasma urealyticum apart. This genome contains 782 putativ e coding sequences (CDSs) covering 91.4% of its length and a function could be assigned to 486 CDSs whilst 92 matched the gene sequences of hypothetic al proteins, leaving 204 CDSs without significant database match. The genom e contains a single set of rRNA genes and only 29 tRNAs genes. The replicat ion origin oriC was localized by sequence analysis and by using the G + C s kew method. Sequence polymorphisms within stretches of repeated nucleotides generate phase-variable protein antigens whilst a recombinase gene is like ly to catalyse the site-specific DNA inversions in major M.pulmonis surface antigens. Furthermore, a hemolysin, secreted nucleases and a glycoprotease are predicted virulence factors. Surprisingly, several of the genes previo usly reported to be essential for a self-replicating minimal cell are missi ng in the M.pulmonis genome although this one is larger than the other myco plasma genomes fully sequenced until now.