Authors : Jia Chen, Su-Fang Fang, Zhong-Yuan Li, Dong-Hui Zhou, Guo-Hua Liu and Xing-Quan Zhu
Abstract: Toxoplasma gondii infects a wide range of animals and humans causing toxoplasmosis. T. gondii rhoptry protein 9 (TgROP9) is expressed only in tachyzoite stage that might be involved in the early stages of invasion and this soluble protein is constituted with putative B-cell epitope but also can trigger a T cell response and exclusively react with CD4 + T cell clone. In this study, researchers examined sequence variation in ROP9 gene among seven T. gondii strains from different hosts and geographical localities by PCR amplification, sequence analysis and phylogenetic reconstruction using Maximum Parsimony (MP). The results showed that the entire genome sequence of the TgROP9 gene was 4555 bp in length and no size variation was detected among all the strains. In addition, there were 26 (0-0.7%) variable nucleotide positions among all isolates with 9 variations of these being in the coding region and the other 11 were distributed among the 4 introns. Phylogenetic analyses revealed that the TgROP9 sequences were not a suitable genetic marker to differentiate T. gondii strains of different genotypes from different hosts and geographical locations. This study determined the TgROP9 genomic sequences of seven T. gondii strains and demonstrated the existence of low sequence variation in TgROP9 gene, suggesting that T. gondii ROP9 may represent a good vaccine candidate against toxoplamosis.
Jia Chen, Su-Fang Fang, Zhong-Yuan Li, Dong-Hui Zhou, Guo-Hua Liu and Xing-Quan Zhu, 2012. Sequence Variation in ROP9 Gene among Toxoplasma gondii Strains from Different Hosts and Geographical Locations. Journal of Animal and Veterinary Advances, 11: 4288-4291.