[DNA sequence polymorphism of Chlamydia trachomatis omp1 gene].
A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed, and the character of omp1 gene of Chlamydia trachomatis was analysed. Urethral or endocervical specimens were collected from 323 patients attending STD clinics in Hengyang, Shanghai, Guangzhou and Jiangmen from November, 2003 to May, 2004. DNA was extracted by usual method, and an approximately 980bp fragment from the major outer membrane protein (omp1) gene of Chlamydia trachomatis was amplified by nested polymerase chain reaction (nPCR). The PCR products were purified by DNA agarose gel purification system and the sequence of the omp1 gene was determined by using an ABI PRISM 3700 Genetic Analyser, and genotyping was performed by BLAST similarity search. Multiple alignment was performed with CLUSTAL package (CLUSTAL X), and a phylogenetic tree was constructed by Mega3 software to illustrate the evolutionary relationships between clinical isolates and reference strains of C. trachomatis obtained from GenBank. All variable sequences were submitted to GenBank by Banklt programe. The overall prevalence of urogenital chlamydial infection was 29.7% (96 of 323). All the 96 C. trachomatis-positive cases were sequenced, and 10 genotypes and 28 genetic variants were detected. The most prevalent genotype was E(34.4%), followed by J(25.0%), D(12.5%), F(8.3%), G(7.3%), H(3.1%), Ba(3.1%), K(3.1%), Da (2.1% ), 1 (1.1%). The distribution of C. trachomatis genotypes in the four cities in sourth China was similar to other countries in the world. The omp1 gene was highly conserved for genotype E and F, but appeared slightly less conserved for other genotypes, where the sequences displayed one or several nucleotide substitutions relatived to the corresponding reference sequence. And a similar recombination was found between genotypes Ba and D in CD1. Phylogenetic tree showed that Chlamydia trachomatis genotypes were mainly divided into three clusters, according to previous grouping in the B, F-G, and C complexes. Clusters F-G and C were characterized by small genetic distances within each cluster, but clusters B displayed larger genetic distances. And the clinical isolates were highly related to the reference strains. It is concluded that the isolated Chlamydia trachomatis strains exhibit remarkable omp1 DNA sequence polymorphism, which can encourage for vaccine design and infection control.
Chen
Li-Li
LL
Institute of Pathogenic Biology, Nanhua University, Hengyang 421001, China. chlili720612@163.com
Wu
Yi-Mou
YM
Lei
Da
D
Wu
Zhi-Zhou
ZZ
Huang
Shu-Jie
SJ
D002690:Chlamydia Infections / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018272:Porins / Q000235:genetics*
D018272:Porins; C071677:omp1 protein, Chlamydia trachomatis