THE PF332 GENE OF PLASMODIUM-FALCIPARUM CODES FOR A GIANT PROTEIN THAT IS TRANSLOCATED FROM THE PARASITE TO THE MEMBRANE OF INFECTED ERYTHROCYTES
THE PF332 GENE OF PLASMODIUM-FALCIPARUM CODES FOR A GIANT PROTEIN THAT IS TRANSLOCATED FROM THE PARASITE TO THE MEMBRANE OF INFECTED ERYTHROCYTES
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DOI：
10.1016/0378-1119(92)90446-v
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发表时间：
1992-01-02
期刊：
影响因子：
3.5
通讯作者：
SCHERF, A
中科院分区：
文献类型：
--
作者：
MATTEI, D;SCHERF, A
我们研究了恶性疟原虫抗原332（Ag332）的基因结构。基因大小估计约为。基于在成熟的无性血液阶段寄生虫中发现的转录物和从基因组DNA产生的绿豆核酸酶片段的大尺寸，20 kb。Pf332基因座的不同区域的基因组和cDNA克隆的序列分析表明，基因产物含有大量的高度简并的谷氨酸（Glu）丰富的重复序列（32%Glu）。该基因在各种恶性疟原虫分离株中显示出显著的限制性片段长度多态性，并定位于11号染色体的亚端粒区。重组332融合蛋白与人单克隆抗体（mAb）33G2强烈反应，其能够在体外测定中抑制寄生的红细胞对黑素瘤细胞系C32的细胞粘附和裂殖子侵入。该mAb识别的表位经常出现在报告的序列中。通过用重组融合蛋白免疫小鼠获得Ag 332单特异性抗体。这些抗体与大寄生虫分子反应，在Western印迹和免疫沉淀分析上，滋养体和寄生虫感染的红细胞的表观分子大小为2500 kDa。使用共聚焦显微镜的免疫荧光研究表明，Ag332从寄生虫输出到感染的红细胞膜内的约1 μ m直径的大泡状结构。
We studied the gene structure of the Plasmodium falciparum antigen 332 (Ag332). The gene size was estimated to be approx. 20 kb based on the large size of both the transcript found in mature asexual blood stage parasites and mung bean nuclease fragment generated from genomic DNA. Sequence analysis of genomic and cDNA clones representing different regions of the Pf332 locus showed that the gene product contains a large number of highly degenerated glutamic acid (Glu)-rich repeats (32% Glu). The gene shows dramatic restriction fragment length polymorphism in various P. falciparum isolates and was mapped to the subtelomeric region of chromosome 11. The recombinant 332 fusion protein reacts strongly with the human monoclonal antibody (mAb) 33G2, which is able to inhibit the cytoadherence of parasitized red blood cells on the melanoma cell line C32 and merozoite invasion in in vitro assays. The epitope recognized by this mAb is found frequently in the reported sequence. Ag332 monospecific antibodies were obtained by immunization of mice with a recombinant fusion protein. These antibodies react with a large parasite molecule with an apparent molecular size of 2500 kDa of trophozoite and schizont-infected erythrocytes on Western blot and by immunoprecipitation analysis. Immunofluorescence studies using a confocal microscope showed that Ag332 is exported from the parasite to the infected red blood cell membrane within large vesicle-like structures of about 1-mu-m diameter.