Dataset Information

The vsp locus of Mycoplasma bovis: gene organization and structural features.

ABSTRACT: Major lipoprotein antigens, known as variable membrane surface lipoproteins (Vsps), on the surface of the bovine pathogen Mycoplasma bovis were shown to spontaneously undergo noncoordinate phase variation between ON and OFF expression states. The high rate of Vsp phenotypic switching was also shown to be linked with DNA rearrangements that occur at high frequency in the M. bovis chromosome (I. Lysnyansky, R. Rosengarten, and D. Yogev, J. Bacteriol. 178:5395-5401, 1996). In the present study, 13 single-copy vsp genes organized in a chromosomal cluster were identified and characterized. All vsp genes encode highly conserved N-terminal domains for membrane insertion and lipoprotein processing but divergent mature Vsp proteins. About 80% of each vsp coding region is composed of reiterated coding sequences that create a periodic polypeptide structure. Eighteen distinct repetitive domains of different lengths and amino acid sequences are distributed within the products of the various vsp genes that are subject to size variation due to spontaneous insertions or deletions of these periodic units. Some of these repeats were found to be present in only one Vsp family member, whereas other repeats recurred at variable locations in several Vsps. Each vsp gene is also 5' linked to a highly homologous upstream region composed of two internal cassettes. The findings that rearrangement events are associated with Vsp phenotypic switching and that multiple regions of high sequence similarity are present upstream of the vsp genes and within the vsp coding regions suggest that modulation of the Vsp antigenic repertoire is determined by recombination processes that occur at a high frequency within the vsp locus of M. bovis.

SUBMITTER: Lysnyansky I

PROVIDER: S-EPMC94094 | biostudies-literature | 1999 Sep

REPOSITORIES: biostudies-literature

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The vsp locus of Mycoplasma bovis: gene organization and structural features.

Lysnyansky I I Sachse K K Rosenbusch R R Levisohn S S Yogev D D

Journal of bacteriology 19990901 18

Major lipoprotein antigens, known as variable membrane surface lipoproteins (Vsps), on the surface of the bovine pathogen Mycoplasma bovis were shown to spontaneously undergo noncoordinate phase variation between ON and OFF expression states. The high rate of Vsp phenotypic switching was also shown to be linked with DNA rearrangements that occur at high frequency in the M. bovis chromosome (I. Lysnyansky, R. Rosengarten, and D. Yogev, J. Bacteriol. 178:5395-5401, 1996). In the present study, 13 ...[more]

PMID: 10482515

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Project description:BackgroundMycoplasma (M.) bovis is a major etiological agent of bovine respiratory disease, which is the most economically costly disease of cattle worldwide. Cattle disease surveillance on M. bovis is increasingly using gene-based techniques, such as multilocus sequence typing (MLST), or genome-based techniques such as core genome MLST that both require only partial genomic data. However, accurate up-to-date surveillance also demands complete, circular genomes that can be used as reference to track the evolution of the different lineages. Yet, in France, two of the main subtypes currently circulating still have no representing genome in public databases. Here, to address this gap, we provide and compare three new complete M. bovis genomes obtained from recent clinical isolates that represent major subtypes circulating in France and Europe.ResultsGenomes were obtained using a hybrid assembly strategy (Illumina and Nanopore) with fine-tuning of settings and inputs used in the Unicycler assembly pipeline, such as size selection of reads and quality trimming of the FASTQ files. The main characteristics and synteny of the genomes were compared. The three genomes mainly differed by their content in terms of mobile genetic elements, i.e. integrative conjugative elements (ICE) and insertion sequences (IS), a feature that impacts their structure. For instance, strain L15527, representing subtype3 (st3), harbours an exceptionally high number of ICEs, which results in a bigger-sized genome than all those previously described and could be associated with the propensity of st3 to gain and fix mutations through chromosomal transfer mechanisms. In contrast, strain F9160, of st1, is very close to the PG45 type strain isolated in 1961 in the USA, and harbours a huge number of IS. These features may be associated with an evolution towards a host-restricted state or in a "closed" host or environment reservoir until a recent re-emergence.ConclusionsWhole-genome comparison of the three French M. bovis subtypes provides valuable resources for future studies combining epidemiology, phylogenetic data, and phylodynamic methods.

Project description:Mycoplasmas are simple, but successful parasites that have the smallest genome of any free-living cell and are thought to have a highly streamlined cellular metabolism. Here, we have undertaken a detailed metabolomic analysis of two species, Mycoplasma bovis and Mycoplasma gallisepticum, which cause economically important diseases in cattle and poultry, respectively. Untargeted gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry analyses of mycoplasma metabolite extracts revealed significant differences in the steady-state levels of many metabolites in central carbon metabolism, while 13C stable isotope labeling studies revealed marked differences in carbon source utilization. These data were mapped onto in silico metabolic networks predicted from genome wide annotations. The analyses elucidated distinct differences, including a clear difference in glucose utilization, with a marked decrease in glucose uptake and glycolysis in M. bovis compared to M. gallisepticum, which may reflect differing host nutrient availabilities. The 13C-labeling patterns also revealed several functional metabolic pathways that were previously unannotated in these species, allowing us to assign putative enzyme functions to the products of a number of genes of unknown function, especially in M. bovis. This study demonstrates the considerable potential of metabolomic analyses to assist in characterizing significant differences in the metabolism of different bacterial species and in improving genome annotation. IMPORTANCE Mycoplasmas are pathogenic bacteria that cause serious chronic infections in production animals, resulting in considerable losses worldwide, as well as causing disease in humans. These bacteria have extremely reduced genomes and are thought to have limited metabolic flexibility, even though they are highly successful persistent parasites in a diverse number of species. The extent to which different Mycoplasma species are capable of catabolizing host carbon sources and nutrients, or synthesizing essential metabolites, remains poorly defined. We have used advanced metabolomic techniques to identify metabolic pathways that are active in two species of Mycoplasma that infect distinct hosts (poultry and cattle). We show that these species exhibit marked differences in metabolite steady-state levels and carbon source utilization. This information has been used to functionally characterize previously unknown genes in the genomes of these pathogens. These species-specific differences are likely to reflect important differences in host nutrient levels and pathogenic mechanisms.

Dataset Information

The vsp locus of Mycoplasma bovis: gene organization and structural features.

Publications

The vsp locus of Mycoplasma bovis: gene organization and structural features.

Similar Datasets

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