MAG2, a Toxoplasma gondii Bradyzoite Stage-Specific Cyst Matrix Protein.
MAG2, a Toxoplasma gondii Bradyzoite Stage-Specific Cyst Matrix Protein.
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MAG2，一种弓形虫缓殖子阶段特异性包囊基质蛋白。
DOI：
10.1128/msphere.00100-20
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发表时间：
2020
期刊：
影响因子：
4.8
通讯作者：
Weiss,LouisM
中科院分区：
文献类型：
--
作者：
Tu,Vincent;Mayoral,Joshua;Yakubu,RamaR;Tomita,Tadakimi;Sugi,Tatsuki;Han,Bing;Williams,Tere;Ma,Yanfen;Weiss,LouisM
刚地弓形虫引起慢性感染，影响到世界上很大一部分人口，这种潜伏感染是弓形虫病重新激活的来源。寄生虫缓慢生长的缓殖子阶段的一个特征是在受感染的细胞内形成一个囊肿，使寄生虫逃脱宿主的免疫反应。本研究通过杂交瘤文库筛选，鉴定出一种新的慢殖子囊基质抗原（MAG）。这种囊肿基质抗原，基质抗原2 (MAG2)，包含14个串联重复序列，由酸性、碱性和脯氨酸残基组成。免疫印迹显示，MAG2的迁移水平高于其预测的分子量，计算分析显示，MAG2的结构高度无序。细胞分离研究表明，MAG2与不溶性和可溶性囊肿基质物质相关，表明它与囊肿内网络（ICN）相互作用。使用光漂白后荧光恢复（FRAP）检查囊肿基质内MAG2的动力学表明，MAG2不容易在囊肿基质内扩散。对MAG1的动力学研究表明，该蛋白在速殖子和慢殖子液泡中具有不同的扩散动力学，并且在没有MAG2的情况下其流动性不会改变。此外，MAG2的缺失并不影响生长、囊形成或囊肿形态。本报告扩展了表征弓形虫刚地囊肿基质蛋白的列表。利用光漂白后荧光恢复（FRAP），我们发现囊肿基质内的基质蛋白主要不是处于移动状态，这进一步证明了囊肿基质内蛋白质的行为。了解寄生虫在慢殖子阶段表达的蛋白质揭示了寄生虫在慢性感染期间的功能。
Toxoplasma gondii causes a chronic infection that affects a significant portion of the world’s population, and this latent infection is the source of reactivation of toxoplasmosis. An attribute of the slowly growing bradyzoite stage of the parasite is the formation of a cyst within infected cells, allowing the parasite to escape the host’s immune response. In this study, a new bradyzoite cystmatrixantigen (MAG) was identified through a hybridoma library screen. This cyst matrix antigen,matrixantigen 2 (MAG2), contains 14 tandem repeats consisting of acidic, basic, and proline residues. Immunoblotting revealed that MAG2 migrates at a level higher than its predicted molecular weight, and computational analysis showed that the structure of MAG2 is highly disordered. Cell fractionation studies indicated that MAG2 was associated with both insoluble and soluble cyst matrix material, suggesting that it interacts with the intracyst network (ICN). Examination of the kinetics of MAG2 within the cyst matrix using fluorescence recovery after photobleaching (FRAP) demonstrated that MAG2 does not readily diffuse within the cyst matrix. Kinetic studies of MAG1 demonstrated that this protein has different diffusion kinetics in tachyzoite and bradyzoite vacuoles and that its mobility is not altered in the absence of MAG2. In addition, deletion of MAG2 does not influence growth, cystogenesis, or cyst morphology.IMPORTANCEThis report expands on the list of characterized Toxoplasma gondii cyst matrix proteins. Using fluorescence recovery after photobleaching (FRAP), we have shown that matrix proteins within the cyst matrix are not mainly in a mobile state, providing further evidence of how proteins behave within the cyst matrix. Understanding the proteins expressed during the bradyzoite stage of the parasite reveals how the parasite functions during chronic infection.