Molecular cloning and expression of a gene encoding Cryptosporidium parvum glycoproteins gp40 and gp15
Molecular cloning and expression of a gene encoding Cryptosporidium parvum glycoproteins gp40 and gp15
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DOI：
10.1128/iai.68.7.4108-4116.2000
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发表时间：
2000-07-01
影响因子：
3.1
通讯作者：
Ward, HD
中科院分区：
文献类型：
--
作者：
Cevallos, AM;Zhang, XP;Ward, HD
小隐孢子虫是世界范围内腹泻疾病的重要病因。介导小孢子虫与宿主细胞相互作用的特定分子和隐孢子虫病发病机制的分子机制尚不清楚。在这项研究中，我们已经证明gp40，一种黏液样糖蛋白，定位于寄生虫入侵阶段的表面和根尖区域，并从其表面脱落。gp40特异性抗体在体外中和感染，并且天然gp40特异性地与宿主细胞结合，暗示这种糖蛋白与小孢子虫附着和侵袭宿主细胞有关。我们克隆并测序了一个名为Cpgp40/15的基因，该基因编码gp40和gp15， gp15是一种抗原性独特的表面糖蛋白，也与小孢子虫与宿主细胞的相互作用有关。对981 bp Cpgp40/15的氨基酸序列分析显示，该序列存在一个n端信号肽、一个聚丝氨酸结构域、多个预测的o -糖基化位点、一个潜在的n -糖基化位点和一个C端疏水区域，这与添加GPI锚点所需要的条件一致。我们的数据表明，Cpgp40/15编码的两个蛋白gp40和gp15是在寄生虫细胞内阶段表达的49 kda前体蛋白的蛋白水解裂解的产物。gp40和gp15的表面定位及其参与宿主-寄生虫相互作用表明，这两种糖蛋白中的任何一种或两种都可以作为隐孢子虫病特异性预防或治疗措施的有效靶点。
Cryptosporidium parvum is a significant cause of diarrheal disease worldwide. The specific molecules that mediate C. parvum-host cell interactions and the molecular mechanisms involved in the pathogenesis of cryptosporidiosis are unknown. In this study we have shown that gp40, a mucin-like glycoprotein, is localized to the surface and apical region of invasive stages of the parasite and is shed from its surface. gp40 specific antibodies neutralize infection in vitro, and native gp40 binds specifically to host cells, implicating this glycoprotein in C. parvum attachment to and invasion of host cells. We have cloned and sequenced a gene designated Cpgp40/15 that encodes gp40 as well as gp15, an antigenically distinct, surface glycoprotein also implicated in C. parvum-host cell interactions. Analysis of the deduced amino acid sequence of the 981-bp Cpgp40/15 revealed the presence of an N-terminal signal peptide, a polyserine domain, multiple predicted O-glycosylation sites, a single potential N-glycosylation site, and a hydrophobic region at the C terminus, a finding consistent with what is required for the addition of a GPI anchor. There is a single copy of Cpgp40/15 in the C. parvum genome, and this gene does not contain introns, Our data indicate that the two Cpgp40/15-encoded proteins, gp40 and gp15, are products of proteolytic cleavage of a 49-kDa precursor protein which is expressed in intracellular stages of the parasite. The surface localization of gp40 and gp15 and their involvement in the host-parasite interaction suggest that either or both of these glycoproteins may serve as effective targets for specific preventive or therapeutic measures for cryptosporidiosis.