Li Jian, Ito Daisuke, Chen Jun-Hu, Lu Feng, Cheng Yang, Wang Bo, Ha Kwon-Soo, Cao Jun, Torii Motomi, Sattabongkot Jetsumon, Tsuboi Takafumi, Han Eun-Taek
Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chunchon, Gangwon-do 200-701, Republic of Korea.
Parasitol Int. 2012 Sep;61(3):443-9. doi: 10.1016/j.parint.2012.02.008. Epub 2012 Feb 25.
Pf12 in Plasmodium falciparum has been characterized as a merozoite surface protein and the Pf12 gene is actively transcribed during schizont stage. An orthologous gene, Pv12, has been identified in genome of P. vivax, but the protein product has not been characterized. The Pv12 is a 362 amino acid long polypeptide encoded by a single exon gene PVX_113775, for which orthologous genes have been identified in other Plasmodium species by bioinformatic approaches. Pv12 contains two predicted six-cysteine (6-Cys) domains, which may be constrained by predicted disulfide bonds, and a transmembrane domain and a predicted GPI anchor attachment site in C-terminal region. The recombinant Pv12 protein is recognized by serum antibodies of patients naturally exposed to P. vivax and the native Pv12 protein from parasite extract is also recognized by immune mouse serum. The Pv12 is localized in rhoptry; an apical organelle of the merozoite, and the localization pattern of Pv12 is distinct from that of Pf12 in P. falciparum. The present study suggests that Pv12 is immunogenic in humans during parasite infection and it could play an important role in erythrocyte invasion.
恶性疟原虫中的Pf12已被鉴定为裂殖子表面蛋白，且Pf12基因在裂殖体阶段活跃转录。在间日疟原虫基因组中已鉴定出一个直系同源基因Pv12，但该蛋白产物尚未得到表征。Pv12是由单外显子基因PVX_113775编码的362个氨基酸长的多肽，通过生物信息学方法已在其他疟原虫物种中鉴定出其直系同源基因。Pv12包含两个预测的六半胱氨酸（6-Cys）结构域，可能受预测的二硫键限制，以及一个跨膜结构域和C端区域的一个预测的糖基磷脂酰肌醇（GPI）锚定附着位点。重组Pv12蛋白可被自然感染间日疟原虫患者的血清抗体识别，来自寄生虫提取物的天然Pv12蛋白也可被免疫小鼠血清识别。Pv12定位于棒状体；裂殖子的顶端细胞器，且Pv12的定位模式与恶性疟原虫中Pf12的定位模式不同。本研究表明，Pv12在寄生虫感染期间对人类具有免疫原性，并且它可能在红细胞入侵中起重要作用。
