The Plasmodium falciparum clag9 gene encodes a rhoptry protein that is transferred to the host erythrocyte upon invasion
The Plasmodium falciparum clag9 gene encodes a rhoptry protein that is transferred to the host erythrocyte upon invasion
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DOI：
10.1111/j.1365-2958.2003.03969.x
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发表时间：
2004-04-01
影响因子：
3.6
通讯作者：
Mattei, D
中科院分区：
文献类型：
--
作者：
Ling, IT;Florens, L;Mattei, D
恶性疟原虫clag（细胞粘附连锁无性基因）家族的第一个特征基因在9号染色体上被鉴定。蛋白质产物（Clag 9）涉及细胞粘附，感染的红细胞与宿主内皮细胞的结合，但这种蛋白质的生化特性的信息很少。其他与clag 9相关的基因也在不同的染色体上被发现。这些基因编码相似的氨基酸序列，但clag 9的保守性最低。在蛋白酶消化和通过质谱法进行肽分析后，在寄生虫、裂殖子和环期寄生虫中检测到Clag 9。使用针对Clag 9的独特区域和针对RhopH 2（裂殖子的RhopH高分子量蛋白质复合物的一个组分）提出的抗血清，免疫荧光共定位这两种蛋白质至裂殖子的顶端区域。免疫电子显微镜共定位Clag 9和RhopH 2专门的棒状体，而不是他们的顶端导管的基部灯泡区域。相同的Clag 9特异性抗体结合RhopH复合物，并且在通过RhopH 2抗体纯化的复合物中检测到蛋白质。Clag 9蛋白也被证明是存在于环阶段的寄生虫，进行通过从以前的周期与RhopH复合物，在一个位置相同的RhopH 2。clag 9基因的转录被证明发生在同一时间作为RhopH复合物，rhoph 2和3的其他成员的基因。结果表明，Clag 9是RhopH复合物的一部分，并表明，在这个复合物中，以前指定的RhopH 1蛋白质是由一个以上的clag基因家族的蛋白质产物。结果怀疑Clag 9在细胞粘附中的直接作用;我们认为RhopH复合物的主要作用是在裂殖子入侵后重塑受感染的红细胞。该复合物可能具有多种功能，这取决于其确切的组成，这可能包括，相对于Clag 9，对细胞粘附机制的贡献。
The first gene characterizing the clag (cytoadherence linked asexual gene) family of Plasmodium falciparum was identified on chromosome 9. The protein product (Clag9) was implicated in cytoadhesion, the binding of infected erythrocytes to host endothelial cells, but little information on the biochemical characteristics of this protein is available. Other genes related to clag9 have been identified on different chromosomes. These genes encode similar amino acid sequences, but clag9 shows least conservation. Clag9 was detected in schizonts, merozoites and ring-stage parasites after protease digestion and peptide analysis by mass spectrometry. Using antisera raised against unique regions of Clag9 and against RhopH2, a component of the RhopH high-molecular-mass protein complex of merozoites, immunofluorescence co-localized the two proteins to the apical region of merozoites. Immunoelectron microscopy co-localized Clag9 and RhopH2 exclusively to the basal bulb region of rhoptries rather than to their apical ducts. The same Clag9-specific antibodies bound the RhopH complex, and the protein was detected in the complex purified by antibodies to RhopH2. Clag9 protein was also shown to be present in ring-stage parasites, carried through from the previous cycle with the RhopH complex, in a location identical to that of RhopH2. Transcription of the clag9 gene was shown to occur at the same time as the genes for other members of the RhopH complex, rhoph2 and 3. The results indicate that Clag9 is part of the RhopH complex and suggest that, within this complex, the protein previously designated RhopH1 is composed of more than one protein product of the clag gene family. The results cast doubt on a direct role for Clag9 in cytoadhesion; we suggest that the primary role of the RhopH complex is in remodelling the infected red blood cell after invasion by the merozoite. The complex may have multiple functions dependent on its exact composition, which may include, with respect to Clag9, a contribution to the mechanism of cytoadhesion.