Boesen, T;
Emmersen, J;
Baczynska, A;
Birkelund, S;
Christiansen, G;
(2004)
The vaa locus of Mycoplasma hominis contains a divergent genetic islet encoding a putative membrane protein.
BMC Microbiology
, 4
, Article 37. 10.1186/1471-2180-4-37.
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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. RESULTS: Mapping of vaa on existing physical maps of five M. hominis isolates by pulsed field gel electrophoresis revealed that vaa is located in a genomic region containing the majority of other characterized membrane protein genes of M. hominis. Sequencing of an 11 kb region containing the vaa locus of M. hominis isolate 132 showed the presence of conserved housekeeping genes at the borders of the region, uvrA upstream and the hitABL operon downstream to vaa. Analysis of 20 M. hominis isolates revealed that the vaa upstream region was conserved whereas the downstream region was highly variable. In isolate 132 this region contained an open reading frame (ORF) encoding a putative 160 kDa membrane protein. Homologous ORFs were present in half of the isolates, whereas this ORF, termed vmp (variable membrane protein), was deleted from the locus in the remaining isolates. Compellingly, the conserved upstream region and variable downstream region of vaa correlates with the genetic structure of vaa itself which consists of a conserved 5' end and a variable 3' end containing a variable number of exchangeable sequence cassettes. CONCLUSION: Our data demonstrate that the vaa locus contains a divergent genetic islet, and indicate pronounced intraspecies recombination. The high variability level of the locus indicate that it is a chromosomal 'hot spot', presumably important for sustaining diversity and a high adaptation potential of M. hominis.
Type: | Article |
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Title: | The vaa locus of Mycoplasma hominis contains a divergent genetic islet encoding a putative membrane protein. |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1186/1471-2180-4-37 |
Publisher version: | http://www.biomedcentral.com/1471-2180/4/37 |
Language: | English |
Additional information: | © 2004 Boesen et al; licensee BioMed Central Ltd. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
UCL classification: | UCL |
URI: | https://discovery.ucl.ac.uk/id/eprint/177457 |
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