Molecular typing of Toxoplasma gondii strains by GRA6 gene sequence analysis
Molecular typing of Toxoplasma gondii strains by GRA6 gene sequence analysis
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DOI：
10.1016/s0020-7519(00)00036-9
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发表时间：
2000-04-24
影响因子：
4
通讯作者：
Pennington, TH
中科院分区：
文献类型：
--
作者：
Fazaeli, A;Carter, PE;Pennington, TH
目的探讨弓形虫致密颗粒抗原GRA 6基因序列多态性作为弓形虫分型标记的应用价值。对来自8个不同酶组（Z1-Z 8）的30株弓形虫GRA 6基因编码区进行了扩增、测序和比较。序列比对发现，在690 bp的24个位点的核苷酸多态性，这与小鼠的毒力。类型I、II和III可以分别根据3个、10个和6个可变位置来彼此区分。在无毒（II型）菌株中存在15 bp和3 bp的两个缺失。除一个例外，所有多态性位点均导致氨基酸替换，15 bp和3 bp的两个缺口导致II型菌株中6个氨基酸的缺失。种内多态性也被发现在强毒组。高度的序列多态性与T. Gondii菌株指出GRA 6基因是该顶复门的菌株表征和分型的良好标记。GRA 6蛋白氨基酸的变化支持了GRA 6蛋白在T.刚地。利用MseI酶切位点的多态性，建立了一种能简单区分T.刚地。(C)2000年澳大利亚寄生虫学会由爱思唯尔科技有限公司出版。保留所有权利。
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, III III) of T. gondii. (C) 2000 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved.