The vaa locus of Mycoplasma hominis contains a divergent genetic islet encoding a putative membrane protein

Boesen, Thomas; Emmersen, Jeppe; Baczynska, Agatha; Birkelund, Svend; Christiansen, Gunna

doi:10.1186/1471-2180-4-37

Cited by 13 publications

(8 citation statements)

References 41 publications

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“…The variable surface protein Lmp1 appears to play a role in suppressing autoaggregation in M. hominis 73 . We therefore examined the major surface lipoproteins including Vaa, the variable membrane protein (Vmp), the Lmp proteins, P120, and P75 to determine whether genetic differences could explain the differential phenotype 74–77 .…”

Section: Resultsmentioning

confidence: 99%

Identification of a gene in Mycoplasma hominis associated with preterm birth and microbial burden in intraamniotic infection

Allen-Daniels

Serrano

Pflugner

et al. 2015

American Journal of Obstetrics and Gynecology

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Objective Microbial invasion of the amniotic cavity is associated with spontaneous preterm labor and adverse pregnancy outcome, and Mycoplasma hominis often is present. However, the pathogenic process by which M. hominis invades the amniotic cavity and gestational tissues, often resulting in chorioamnionitis and preterm birth, remains unknown. We hypothesized that strains of M. hominis vary genetically with regards to their potential to invade and colonize the amniotic cavity and placenta. Study Design We sequenced the entire genomes of 2 amniotic fluid isolates and a placental isolate of M. hominis from pregnancies that resulted in preterm births and compared them with the previously sequenced genome of the Type strain PG21. We identified genes that were specific to the amniotic fluid/placental isolates. We then determined the microbial burden and the presence of these genes in another set of subjects from whom samples of amniotic fluid had been collected and were positive for M. hominis. Results We identified 2 genes that encode surface-located membrane proteins (Lmp1 and Lmp-like) in the sequenced amniotic fluid/placental isolates that were severely truncated in PG21. We also identified, for the first time, a microbial gene of unknown function that is referred to in this study as gene of interest C that was significantly associated with bacterial burden in amniotic fluid and the risk of preterm delivery in patients with preterm labor. Conclusion A gene in M. hominis was identified that is associated significantly with colonization and/or infection of the upper reproductive tract during pregnancy and with preterm birth.

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Section: Resultsmentioning

confidence: 99%

Identification of a gene in Mycoplasma hominis associated with preterm birth and microbial burden in intraamniotic infection

Allen-Daniels

Serrano

Pflugner

et al. 2015

American Journal of Obstetrics and Gynecology

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“…The observed differences in PFGE patterns may be due to restriction sites located in variable regions or to recombination. Indeed, results from previous analysis indicated that a high levels of intragenic and intergenic recombination occurred in M. hominis , and these recombination levels are presumably important for the adaptation potential of this species [11,14]. …”

Section: Discussionmentioning

confidence: 99%

“…Other molecular typing methods based on sequence analyses of the p75 , p120’ and vaa genes have been developed [11-13]. An MLST approach based on the sequence analysis of six housekeeping genes and one gene encoding a membrane protein was conducted for 20 M. hominis isolates [14].…”

Section: Introductionmentioning

confidence: 99%

Diversity of Mycoplasma hominis clinical isolates from Bordeaux, France, as assessed by multiple-locus variable-number tandem repeat analysis

et al. 2013

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BackgroundMycoplasma hominis is an opportunistic human mycoplasma species that can cause various urogenital infections and, less frequently, extragenital infections. The objective of this work was to study the genetic diversity of this species using a molecular typing method based on multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA).ResultsThe genome content of M. hominis PG21 was analysed for tandem repeats (TRs), and five of the 130 TRs identified were selected for use in an MLVA assay. The method was based on GeneScan analysis of VNTR loci using multiplex PCR with fluorescent dyes and resolution by capillary electrophoresis. This approach was used on a collection of 210 urogenital and extragenital French clinical isolates collected between 1987 and 2009. Forty MLVA types were found. The discriminatory index of our MLVA scheme was 0.924. Using this new typing tool, persistent infection was suggested for six patients and new infection for one patient. Furthermore, mother-to-child transmission was confirmed in the two cases studied. Application of MLVA to a wide range of M. hominis isolates revealed high genotypic diversity and no obvious link between the MLVA type and the isolate year of collection, the patient’s age or sex, the anatomical origin of the isolates or resistance to antibiotics was found.ConclusionsOur MLVA scheme highlights the high genetic heterogeneity of the M. hominis species. It seems too discriminatory to be used for large epidemiological studies but has proven its usefulness for molecular studies at the individual level.

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“…Using these conditions, we demonstrated, after screening the 1200-clone library, that four and two M. hominis mutants were successfully generated in two targeted genes previously associated with the bacterium’s pathogenicity, the vaa gene involved in cytadherence [ 12 ] and the oppA gene involved in oligopeptide binding and the ecto ATPase activity [ 13 , 15 ], respectively. Because the ATPase activity of the OppA protein is due mainly to the CS3, Walker B and Walker A gene regions [ 14 ], a fragment of 1144 bp encompassing these regions was chosen.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, we used ethyl methanesulfonate (EMS) that introduces C-G to T-A transition mutations to generate a library of M. hominis mutants. As a proof of principle, mutagenized organisms were screened for mutations in two target genes, the vaa gene encoding the variable adherence-associated (Vaa) adhesin lipoprotein [ 12 ] and the oppA gene encoding the substrate binding subunit of an oligopeptide permease and the main ecto ATPase of the bacteria [ 13 , 14 ]. The generated vaa - and oppA -mutants were fully sequenced and evaluated using two functional assays, an adhesion test to HeLa cells for vaa -mutants and an ATPase activity test for oppA -mutants.…”

Section: Introductionmentioning

confidence: 99%

Generation of Mycoplasma hominis gene-targeted mutants by targeting-induced local lesions in genomes (TILLING)

et al. 2018

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BackgroundMycoplasma hominis is a human urogenital pathogen involved in gynaecological, neonatal and extra-genital infections. However, no versatile genetic tools are currently available to study the pathogenicity of this bacterium. Targeting-Induced Local Lesions IN Genomes (TILLING) is a reverse-genetic method that combines point mutations induced by chemical mutagenesis with a DNA screening technique. We used ethyl methanesulfonate (EMS) that introduces C-G to T-A transition mutations to generate a library of M. hominis mutants. As a proof of concept, mutagenized organisms were screened for mutations in two target genes previously associated with the mycoplasma pathogenicity, the vaa gene encoding an adhesin lipoprotein and the oppA gene encoding the main ectoATPase of the bacterium. The resulting mutants were evaluated using functional assays, an adhesion to HeLa cell assay for vaa-mutants and an ATPase activity test for oppA-mutants.ResultsA 1200-clone library was generated by exposing M. hominis PG21 to 9 mg/mL EMS for 3 h. To identify mutants of interest, targeted gene fragments were amplified, heat-denatured, slowly reannealed and digested with the mismatch-specific endonuclease ENDO1. If multiple alleles were present in the PCR amplicons, these alleles formed heteroduplexes during reannealing that were specifically cleaved by ENDO1 at mismatching positions.A total of four vaa-mutants and two oppA-mutants harbouring missense mutations were obtained and fully sequenced. Zero to eight additional mutations were identified in the genomes of each mutant. The vaa-mutants were tested for adhesion to immobilized HeLa cells but their adhesion was not significantly different from the adhesion of M. hominis PG21. One of the two oppA-mutants that were tested for ATPase activity presented a higher affinity for its ATP substrate than the parental strain.ConclusionFor the first time, we demonstrated that M. hominis gene-targeted mutants could be successfully obtained using this TILLING strategy. In the absence of robust genetic tools for studying M. hominis, the TILLING strategy that can target any gene of the genome could help to elucidate gene functions and to better understand the pathogenesis of this human pathogenic species.

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The vaa locus of Mycoplasma hominis contains a divergent genetic islet encoding a putative membrane protein

Abstract: Background: The Mycoplasma hominis vaa gene encodes a highly variable, surface antigen involved in the adhesion to host cells. We have analysed the structure of the vaa locus to elucidate the genetic basis for variation of vaa.

Cited by 13 publications

References 41 publications

Identification of a gene in Mycoplasma hominis associated with preterm birth and microbial burden in intraamniotic infection

Identification of a gene in Mycoplasma hominis associated with preterm birth and microbial burden in intraamniotic infection

Diversity of Mycoplasma hominis clinical isolates from Bordeaux, France, as assessed by multiple-locus variable-number tandem repeat analysis

Generation of Mycoplasma hominis gene-targeted mutants by targeting-induced local lesions in genomes (TILLING)

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