DIFFERENTIAL LOCALIZATION OF FULL-LENGTH AND PROCESSED FORMS OF PF83/AMA-1 AN APICAL MEMBRANE ANTIGEN OF PLASMODIUM-FALCIPARUM MEROZOITES
DIFFERENTIAL LOCALIZATION OF FULL-LENGTH AND PROCESSED FORMS OF PF83/AMA-1 AN APICAL MEMBRANE ANTIGEN OF PLASMODIUM-FALCIPARUM MEROZOITES
复制标题
DOI：
10.1016/0166-6851(94)90096-5
复制
发表时间：
1994-09-01
影响因子：
1.5
通讯作者：
THOMAS, AW
中科院分区：
文献类型：
--
作者：
NARUM, DL;THOMAS, AW
恶性疟原虫PF 83/AMA-1是一种高度保守的83-kDa顶端膜抗原，在晚期裂殖子中表达，位于裂殖子顶端，在裂殖子破裂时或前后被加工成44/42-kDa的双联体。加工的形式可以与裂殖子表面结合。我们感兴趣的是进一步分析PF 83/AMA-1（一种疟疾疫苗候选物）的合成和加工时间以及亚细胞定位，使用针对PF 83/AMA-1开发的单克隆抗体（mAb）。使用[S-35]蛋氨酸代谢标记的无性血液期寄生虫，结合间接单和双重免疫荧光，我们已经确定，以与PK 66/AMA-1类似的方式，PF 83/AMA-1的蛋白表达仅限于具有大于8个核的晚期树突。PF 83/AMA-1通过将N-末端肽切割成66-kDa分子而被快速合成后加工。83-和66-kDa的分子最初都位于裂殖子的顶端。在恶性疟原虫（7 G8株和CVD-1克隆）中，全长83-kDa分子在裂殖子释放后保持顶端限制。然而，加工的66-kDa形式可以在裂殖体破裂和裂殖子释放时或前后与裂殖子表面周向缔合。在裂殖子侵入后，PF 83/AMA-1的加工形式存在于早期环期寄生虫中。棒状体相关蛋白RAP-1的比较分析显示棒状体组分的协调和区室化释放。
A well conserved 83-kDa apical membrane antigen of Plasmodium falciparum, PF83/AMA-1 is expressed in late-stage schizonts; is localized within the merozoite apex; and is processed to a 44/42-kDa doublet at, or around, the time of schizont rupture. The processed forms can associate with the merozoite surface. We were interested to further analyze the timing of synthesis and processing, and subcellular localization of PF83/AMA-1, a malaria vaccine candidate, using monoclonal antibodies (mAbs) developed against PF83/AMA-1 Using [S-35]methionine metabolically labeled asexual blood stage parasites, in combination with indirect single and dual immunofluorescence, we have determined that, in similar fashion to PK66/AMA-1, protein expression of PF83/AMA-1 is restricted to late-stage schizonts with greater than 8 nuclei. PF83/AMA-1 is post-synthetically processed rapidly by cleavage of an N-terminal peptide to a 66-kDa molecule. Both the 83- and the 66-kDa molecules are initially localized at the merozoite apex. In P. falciparum (7G8 strain and CVD-1 clone) the full-length 83-kDa molecule remains apically restricted following merozoite release. However, the processed 66-kDa form can become circumferentially associated with the merozoite surface at or around the time of schizont rupture and merozoite release. After merozoite invasion a processed form of PF83/AMA-1 is present in early ring stage parasites. Comparative analysis of a rhoptry associated protein RAP-1, shows a co-ordinated and compartmentalized release of rhoptry components.