Bradyzoite Pseudokinase 1 Is Crucial for Efficient Oral Infectivity of the Toxoplasma gondii Tissue Cyst
Bradyzoite Pseudokinase 1 Is Crucial for Efficient Oral Infectivity of the Toxoplasma gondii Tissue Cyst
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DOI：
10.1128/ec.00343-12
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发表时间：
2013-03-01
期刊：
影响因子：
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通讯作者：
Boothroyd, John C.
中科院分区：
文献类型：
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作者：
Buchholz, Kerry R.;Bowyer, Paul W.;Boothroyd, John C.
弓形虫缓殖子期形成的组织包囊是宿主持续感染和经口传播的必要条件。缓殖子假激酶1（BPK 1）是囊壁的一种成分，但以前对其功能一无所知。在这里，我们表明，免疫沉淀的BPK 1从体外缓殖子培养，感染后4天，确定至少有四个相关蛋白：MAG 1，MCP 4，GRA 8和GRA 9。为了确定BPK 1的作用，产生了bPK 1基因座缺失的弓形虫菌株。在体外和体内研究了BPK 1敲除菌株（Delta bpk 1）。在体外囊肿形成方面没有发现缺陷，并且在腹膜内（i. p.）感染Delta bpk 1速殖子，尽管Delta bpk 1包囊在8 wpi时显著小于亲本或BPK 1补充菌株。胃蛋白酶-酸处理4 wpi体内包囊显示，Delta bpk 1寄生虫对该处理比亲本和补充菌株显著更敏感。与此一致，与亲本和补充菌株相比，4个wpi Delta bpk 1包囊显示出降低的引起口腔感染的能力。总之，这些数据表明BPK 1在弓形虫包囊的体内发育和感染性中起着至关重要的作用。
The tissue cyst formed by the bradyzoite stage of Toxoplasma gondii is essential for persistent infection of the host and oral transmission. Bradyzoite pseudokinase 1 (BPK1) is a component of the cyst wall, but nothing has previously been known about its function. Here, we show that immunoprecipitation of BPK1 from in vitro bradyzoite cultures, 4 days postinfection, identifies at least four associating proteins: MAG1, MCP4, GRA8, and GRA9. To determine the role of BPK1, a strain of Toxoplasma was generated with the bpk1 locus deleted. This BPK1 knockout strain (Delta bpk1) was investigated in vitro and in vivo. No defect was found in terms of in vitro cyst formation and no difference in pathogenesis or cyst burden 4 weeks postinfection (wpi) was detected after intraperitoneal (i.p.) infection with Delta bpk1 tachyzoites, although the Delta bpk1 cysts were significantly smaller than parental or BPK1-complemented strains at 8 wpi. Pepsin-acid treatment of 4 wpi in vivo cysts revealed that Delta bpk1 parasites are significantly more sensitive to this treatment than the parental and complemented strains. Consistent with this, 4 wpi Delta bpk1 cysts showed reduced ability to cause oral infection compared to the parental and complemented strains. Together, these data reveal that BPK1 plays a crucial role in the in vivo development and infectivity of Toxoplasma cysts.