Colomer-Gould V, Enea V
Department of Medical and Molecular Parasitology, New York University Medical Center, New York 10010.
Mol Biochem Parasitol. 1990 Nov;43(1):51-8. doi: 10.1016/0166-6851(90)90129-a.
The circumsporozoite (CS) gene encodes the most immunogenic component of the plasmodial sporozoites. The immunodominant epitope-encoding domain of the CS gene shows sequences that are repeated in tandem. A detailed analysis of the CS repeats of certain closely related malaria parasites (strains of Plasmodium cynomolgi, Plasmodium knowlesi, and Plasmodium vivax) showed that they evolve rapidly yet are well conserved within the gene. We were interested in studying whether the CS repeats of Plasmodia more distantly related to these species evolve in a similar manner. To this end, we isolated and characterized the Plasmodium yoelii nigeriensis CS gene. A comparative analysis of its sequence with that of Plasmodium yoelii yoelii shows that both have three sets of repeats, termed PR, R1, and R2. The R1 and basically also the R2 sequences show the features observed in most CS repeats, i.e., they evolve rapidly and are nearly perfectly tandemly repeated. In contrast, the PR repeats are not internally conserved nor divergent in sequence. The implications of these findings for the evolution of the CS repeats are discussed.
环子孢子（CS）基因编码疟原虫子孢子中最具免疫原性的成分。CS基因的免疫显性表位编码结构域显示出串联重复的序列。对某些密切相关的疟原虫（食蟹猴疟原虫、诺氏疟原虫和间日疟原虫的菌株）的CS重复序列进行的详细分析表明，它们进化迅速，但在基因内却高度保守。我们感兴趣的是研究与这些物种亲缘关系更远的疟原虫的CS重复序列是否以类似的方式进化。为此，我们分离并鉴定了约氏疟原虫尼日利亚株的CS基因。将其序列与约氏疟原虫约氏株的序列进行比较分析表明，两者都有三组重复序列，称为PR、R1和R2。R1以及基本上R2序列都显示出在大多数CS重复序列中观察到的特征，即它们进化迅速且几乎完全串联重复。相比之下，PR重复序列在内部不保守，序列也没有差异。讨论了这些发现对CS重复序列进化的意义。
