三日疟原虫表面抗原蛋白基因的初步研究

用两种人工合成的寡核苷酸探针筛选三日疟原虫红内期DNA基因组库。结果表明,三日疟原虫无性期表面可能存在与恶性疟原虫表面类似的P190抗原蛋白,这一蛋白也呈多形型。筛选结果得到两个DNA基因克隆MSA-1和MSA-2,其大小分别为5.5kb和3.5kb。杂交分析证实它们分别类似于恶性疟原虫P190基因的MAD20型和K1型。对MSA-1和MSA-2限制性内切酶谱研究发现MSA-1基因段内有1个BglⅡ位点、1个EcoRⅠ位点、2个XbaⅠ位点、1个HindⅡ位点和1个PstⅠ位点;而MSA-2基因段中只有1个HindⅡ位点。

PRELIMINARY STUDY ON THE SURFACE ANTIGEN GENE OF PLASMODIVM MALARIAE

The genomic Hind III lambda gt1149 library from Plasmodium malariae was screened with two types of oligonucleotides, both of which were from the P190 gene of P. falciparum. One, MAD20 type, was made from spanning nucleotides 4488-4562 in the P190 gene of MAD20 strain and another, K1 type, was made from spanning nucleotides 3652-3692 in the P190 of K1 strain. Both were end-labelled with 32P-ATP as probes before hybridization. Two clones were selected. One clone, designated lambda MSA-1, was specifically recognized by the MAD20 type oligo probe; the other, designated lambda MSA-2, by the K1 type oligo probe. lambda MSA-1 and lambda MSA-2 inserts were obtained by Hind III digestion of the two clone phage DNA. The analysis of the two inserts showed that the size of lambda MSA-1 is 5.5 kb whilst that of lambda MSA-2 is 3.5kb. The MSA-1 and MSA-2 inserts recloned into PUC8 were digested with the restriction enzymes Bg1 II, EcoR I, Xba I, Hind II and Pst I. The results showed that the MSA-1 DNA had one Bg1 II site, one EcoR I site, two Xba I sites, one Hind II site and one Pst I site. The MSA-2 DNA had only one Hind II site. The surface antigen gene of P. malariae was little known. This result also showed that there was probably an analogue of P190 on the surface of P. malariae, and they might fall into two types. This study is informative for further investigation on malariae parasites.