SUBTELOMERIC CHROMOSOME DELETIONS IN FIELD ISOLATES OF PLASMODIUM-FALCIPARUM AND THEIR RELATIONSHIP TO LOSS OF CYTOADHERENCE INVITRO
SUBTELOMERIC CHROMOSOME DELETIONS IN FIELD ISOLATES OF PLASMODIUM-FALCIPARUM AND THEIR RELATIONSHIP TO LOSS OF CYTOADHERENCE INVITRO
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DOI：
10.1073/pnas.86.7.2428
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发表时间：
1989-04-01
影响因子：
11.1
通讯作者：
BROWN, GV
中科院分区：
文献类型：
--
作者：
BIGGS, BA;KEMP, DJ;BROWN, GV
亚端粒缺失是恶性疟原虫几种抗原表达缺失的原因，包括结节相关的富含组氨酸的蛋白(Kahrp)。这种缺失可以通过二维脉冲梯度电泳法(PFGE)检测到。在PFGE中，用Apa I切割在维度1分离的染色体，在维度2确定端粒片段的大小。这项敏感的技术使我们能够从两个方面探讨端粒缺失在恶性疟原虫生物学中的作用。首先，我们证明了类似于体外发生的亚端粒缺失也发生在野外分离株中。其次，我们证明了在培养的分离株中，亚端粒缺失和“细胞黏附”表型的丧失之间存在相关性。从细胞粘附性克隆株ItG2F6中获得亚克隆，并检测其细胞黏附、“结节”表达和感染红细胞与兔抗血清的凝集性。在这三个特征上都与野生型不同的亚克隆中，二维PFGE检测到的唯一染色体变化是2号染色体一端约100千碱基的缺失，包括编码kahrp的基因和命名为ref20的亚端粒重复序列。
Subtelomeric deletions are responsible for the loss of expression of several Plasmodium falciparum antigens, including the knob-associated histidine-rich protein (KAHRP). Such deletions are detectable by two-dimensional pulsed-field gradient electrophoresis (PFGE) in which the chromosome separated in dimension 1 are cleaved with Apa I, and the sizes of telomeric fragments are determined in dimension 2. This sensitive technique has enabled us to examine the role of subtelomeric deletions in two aspects of the biology of Plasmodium falciparum. First, we show that similar subtelomeric deletions to those that occur in vitro also occur in field isolates. Second, we demonstrate a correlation between subtelomeric deletions and loss of the phenotype of "cytoadherence" in cultured isolates. Subclones were generated from the cytoadherent cloned isolate ItG2F6, and their phenotypes were examined with respect to cytoadherence, the expression of "knobs", and agglutination of infected erythrocytes with rabbit antiserum. The only chromosomal change detectable by two-dimensional PFGE among subclones that differ from wild type in each of these three characteristics is a deletion of approximately 100 kilobases at one end of chromosome 2. This deletion includes the gene coding for KAHRP and the subtelomeric repeat designated rep20.