Molecular typing of Toxoplasma gondii strains by GRA6 gene sequence analysis.
Int J Parasitol
; 30(5): 637-42, 2000 Apr 24.
Article
em En
| MEDLINE
| ID: mdl-10779578
ABSTRACT
The utility of sequence polymorphisms in the dense granule antigen GRA6 gene as typing markers for Toxoplasma gondii was investigated. The coding region of GRA6 was amplified, sequenced and compared for 30 Toxoplasma strains from eight different zymodemes (Z1-Z8). Sequence alignment identified nucleotide polymorphisms at 24 positions out of 690 bp, which correlated with murine-virulence. Types I, II, and III could be distinguished from each other on the basis of three, 10, and six variable positions, respectively. Two deletions of 15 bp and 3 bp existed in the avirulent (type II) strains. With one exception, all polymorphic positions resulted in amino acid substitutions, and the two gaps of 15 bp and 3 bp caused the deletion of six amino acids in type II strains. Intra-specific polymorphisms were also found in the virulent group. A high degree of sequence polymorphism correlating with the phenotypes of T. gondii strains points to the GRA6 gene being a good marker for strain characterisation and typing of the isolates of this apicomplexan. The large variety of amino acid changes supports the view that the GRA6 protein plays an important role in the antigenicity and pathogenicity of T. gondii. The existence of polymorphic restriction sites for endonuclease MseI was used to develop a PCR-RFLP method which could simply differentiate the three different groups (types I, II, III) of T. gondii.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Toxoplasma
/
Proteínas de Protozoários
/
Antígenos de Protozoários
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article