Kumar N, Syin C A, Carter R, Quakyi I, Miller L H
Department of Immunology and Infectious Diseases, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, MD 21205.
Proc Natl Acad Sci U S A. 1988 Sep;85(17):6277-81. doi: 10.1073/pnas.85.17.6277.
Genes homologous to heat shock protein 70 have been described in parasitic protozoa. It has been proposed that they may be important to the parasite as it moves from the vertebrate host at 37 degrees C to the insect. We now describe a genomic DNA clone isolated from Plasmodium falciparum that encodes a protein similar in sequence to a mammalian heat shock-related protein, the 78-kDa glucose-regulated protein of rat and hamster. The gene is expressed during the erythrocytic stage in both asexual and sexual parasites (RNA blot analysis) and a 72-kDa protein is immunoprecipitated from erythrocytic stage parasites. Importantly, the sequence of the clone is similar to the canonical sequence at the carboxyl termini of glucose-regulated proteins of mammals that determines their localization within endoplasmic reticulum. Since the parasite sequence has only three (Asp-Glu-Leu) of the four carboxyl-terminal amino acids, its location and its function within the parasite remain to be determined.
在寄生原生动物中已发现与热休克蛋白70同源的基因。有人提出，当寄生虫从37摄氏度的脊椎动物宿主转移至昆虫体内时，这些基因可能对寄生虫很重要。我们现在描述了一个从恶性疟原虫中分离出的基因组DNA克隆，它编码一种蛋白质，其序列与哺乳动物热休克相关蛋白、大鼠和仓鼠的78 kDa葡萄糖调节蛋白相似。该基因在红细胞阶段的无性和有性寄生虫中均有表达（RNA印迹分析），并且从红细胞阶段的寄生虫中免疫沉淀出一种72 kDa的蛋白质。重要的是，该克隆的序列与哺乳动物葡萄糖调节蛋白羧基末端的典型序列相似，该序列决定了它们在内质网中的定位。由于寄生虫序列在羧基末端四个氨基酸中只有三个（天冬氨酸-谷氨酸-亮氨酸），其在寄生虫中的位置和功能仍有待确定。
