Comparison of the major outer-membrane protein (MOMP) gene of mouse pneumonitis (MoPn) and hamster SFPD strains of Chlamydia trachomatis with other Chlamydia strains.

Abstract

Restriction fragments containing the major outer-membrane protein (MOMP) gene from two nonhuman (rodent) strains of Chlamydia trachomatis, the mouse pneumonitis (MoPn) strain and the SFPD strain isolated from hamsters with transmissible proliferative ileitis, were cloned and sequenced. The MOMP genes of both MoPn and SFPD encode an identical 22-amino acid leader peptide and mature polypeptides of 365 and 382 amino acids, respectively. Alignment of the MOMP genes of the two rodent strains revealed 91% identity. By comparison with other known chlamydial MOMP gene sequences, there was 80%-83% identity with human biovars strains of C. trachomatis, and there was 69%-70% identity with C. psittaci and C. pneumoniae strains. The main differences in these sequences were clustered into four variable domains. A minimum-length evolutionary tree was constructed on the basis of the MOMP gene variable positions by using PIMA package software. The minimum mutation distances indicated that (i) the MOMP genes of all chlamydial strains may have evolved from a common ancestor; (ii) all the strains of C. trachomatis compose one of the subtrees, and strains of C. psittaci and C. pneumoniae compose the other subtree; and (iii) in the C. trachomatis subtree, the human and the rodent strains are divided into two clusters. The branching pattern of this evolutionary tree is generally consistent with current classification based on serological, morphological, and other biological characteristics.

Chlamydia pneumoniae Is Genetically Diverse in Animals and Appears to Have Crossed the Host Barrier to Humans on (At Least) Two Occasions

“…The 16S rRNA and ompA genes have been extensively used to distinguish and phylogenetically group chlamydial species [24]–[27]. Although not as informative as our newly identified target genes, our analysis showed that 16S rRNA, ompA and omcB were evolving in much the same way as our target genes.…”

Novel molecular markers of Chlamydia pecorum genetic diversity in the koala (Phascolarctos cinereus)

“…In an attempt to understand these questions, Jackson et al, have previously performed fine-detailed epidemiological surveys of C. pecorum -infected koala populations, revealing that C. pecorum is genetically very diverse [7]. This analysis was performed on short variable domain IV (VDIV) sequence fragments of the omp A gene, encoding the surface-exposed major outer membrane protein (MOMP) which is common to all members of the Chlamydiaceae [15]. There are currently eight omp A VDIV genotypes that have been identified, following several studies of geographically isolated koala populations in Australia [7,8,14,16,17].…”

Immunopathogenesis of Chlamydial Infections

“…While it has never been isolated from any animal but laboratory mice and hamsters (Zhang et al 1993), there is evidence of rodent chlamydial infection in nature (Ramsey et al 2016). Intravaginal inoculation with C. muridarum resembles an acute genital C. trachomatis infection in women.…”