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Updated: Jun 2, 2026
Forward Genetic Approaches in Chlamydia trachomatis
Published on: October 23, 2013
Genetic variability of Chlamydophila abortus strains assessed by PCR-RFLP analysis of polymorphic membrane
Michelle Sait1, Ewan M Clark, Nicholas Wheelhouse
1Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, UK. michelle.sait@moredun.ac.uk
Abstract:
This study used PCR-RFLP to investigate the genetic variability of pmp-encoding genes from fifty-two Chlamydophila abortus (C. abortus) strains originating from abortion cases from various geographical regions and host species. Six primer pairs were used to PCR-amplify DNA fragments encoding eighteen pmps. PCR products were digested using four restriction endonucleases and Bayesian methodologies were used to compare RFLP profiles and assign strains to a RFLP genotype. Strains could be assigned to 2 genotypes in the region encoding pmp18D, 3 genotypes in the regions encoding pmp1A-pmp2B, pmp3E-pmp6H and pmp11G-pmp15G, 4 genotypes in the region encoding pmp7G-pmp10G and 5 genotypes in the region encoding pmp16G-pmp17G. In all regions, the majority of strains (88.4-96.1%) had the same genotype as the reference strain S26/3. No correlation could be made between genotype, host species or geographical origin except for the two variant Greek strains, LLG and POS, which formed a discrete genotype in all pmp-encoding regions except pmp18D. Relative rates of evolution calculated for each pmp-encoding gene locus suggest that differing selective pressures and functional constraints may exist on C. abortus polymorphic membrane proteins. These findings suggest that although intraspecies heterogeneity of pmp-encoding genes in C. abortus is low, the sequence heterogeneity should be an important consideration when using pmps as the basis for novel diagnostics or vaccine development.
Insights
Genetic variability in Chlamydophila abortus (C. abortus) polymorphic membrane protein (pmp) genes was low among strains. However, sequence variations exist, impacting potential diagnostics and vaccines.
Area of Science:
- Veterinary Microbiology
- Molecular Biology
- Genetics
Background:
- Chlamydophila abortus (C. abortus) is a significant cause of abortion in livestock.
- Polymorphic membrane proteins (pmps) are crucial for C. abortus pathogenesis and are potential targets for diagnostics and vaccines.
- Understanding the genetic diversity of pmp-encoding genes is essential for developing effective control strategies.
Purpose of the Study:
- To investigate the genetic variability of pmp-encoding genes in C. abortus strains.
- To determine the RFLP genotypes of pmp genes across different geographical regions and host species.
- To assess the implications of genetic heterogeneity for diagnostic and vaccine development.
Main Methods:
- Fifty-two C. abortus strains from abortion cases were analyzed.
- PCR-RFLP was employed to amplify and digest DNA fragments encoding eighteen pmps.
- Bayesian methodologies were used to assign strains to RFLP genotypes.
Main Results:
- Most C. abortus strains (88.4-96.1%) shared the same pmp genotypes as the reference strain S26/3.
- Variable genotypes were observed across different pmp-encoding regions, with 2 to 5 genotypes identified.
- Two Greek strains (LLG and POS) exhibited a distinct genotype across most pmp regions.
- Relative rates of evolution suggested varying selective pressures on pmp genes.
Conclusions:
- Intraspecies genetic heterogeneity of pmp-encoding genes in C. abortus is generally low.
- Sequence heterogeneity, though limited, is a critical consideration for developing pmp-based diagnostics and vaccines.
- Further research into selective pressures on pmps can inform future vaccine and diagnostic design.
