Alano P, Roca L, Smith D, Read D, Carter R, Day K
Laboratorio di Biologia Cellulare, Istituto Superiore di Sanità, Rome, Italy.
Exp Parasitol. 1995 Sep;81(2):227-35. doi: 10.1006/expr.1995.1112.
Some molecular characteristics of Plasmodium falciparum lines which do not produce gametocytes are described. Parasites carrying a subtelomerically deleted chromosome 9 cannot form even the earliest forms of gametocytes, detectable with antibodies against the gametocyte-specific antigen Pfg27. In a parasite culture of clone HB3, in which both intact and deleted forms of chromosome 9 are present, full-length chromosome 9 molecules are retained mainly in gametocytes. These data suggest that the subtelomeric portion of chromosome 9 is required at an early stage of gametocytogenesis. Parasite subclones derived from gametocyte producing clone 3D7, which completely lost ability to produce gametocytes, are also described. Unlike the previous gametocyteless lines, these parasites stably maintain a full-length chromosome 9 and the ability to cytoadhere to C32 melanoma cells after prolonged asexual propagation. Their defect in sexual development is therefore genetically and functionally distinct from that of parasites carrying a deleted chromosome 9. Gametocyteless subclones derived from 3D7 do not produce any Pfg27 mRNA, while this gene is anomalously expressed in asexual stage parasites of two lines of a different genetic background, 1776sel8 and C10, one able and the other unable to produce gametocytes.
描述了不产生配子体的恶性疟原虫株的一些分子特征。携带9号染色体亚端粒缺失的寄生虫甚至不能形成最早形式的配子体，用针对配子体特异性抗原Pfg27的抗体无法检测到。在克隆HB3的寄生虫培养物中，9号染色体的完整和缺失形式都存在，全长9号染色体分子主要保留在配子体中。这些数据表明，9号染色体的亚端粒部分在配子体发生的早期阶段是必需的。还描述了源自产生配子体的克隆3D7的寄生虫亚克隆，这些亚克隆完全丧失了产生配子体的能力。与之前的无配子体株不同，这些寄生虫在长期无性繁殖后能稳定地保持全长9号染色体以及细胞黏附于C32黑色素瘤细胞的能力。因此，它们在有性发育方面的缺陷在遗传和功能上与携带9号染色体缺失的寄生虫不同。源自3D7的无配子体亚克隆不产生任何Pfg27 mRNA，而该基因在不同遗传背景的两个株系（1776sel8和C10，一个能产生配子体，另一个不能产生配子体）的无性阶段寄生虫中异常表达。
