3种恶性疟原虫红内期抗原基因的测序和序列分析

SEQUENCE DETERMINATION AND ANALYSIS OF THREE BLOOD STAGE ANTIGEN GENES OF PLASMODIUM FALCIPARUM

目的 测定我国恶性疟原虫海南株 (FCC1/ HN)谷氨酸富集蛋白 (GARP)、丝氨酸重复抗原 (SERA)和裂殖子表面蛋白 1(MSA1)基因序列 ,并进行序列分析。 方法 采用 PCR技术从恶性疟原虫 FCC1/ HN株基因组 DNA中扩增 GARP、SERA和 MSA1基因片段 ,分别插入到测序载体上进行测序。应用 DNAstar软件辅助分析 3种抗原基因的结构及 3种抗原在不同恶性疟原虫株间的分化情况。 结果 恶性疟原虫 FCC1/ HN株 GARP基因全长 2 2 6 3bp,编码6 82个氨基酸残基 ,谷氨酸占 2 3.6 1% ,包含 5个典型的氨基酸重复序列 ;SERA基因全长 344 8bp,编码 995个氨基酸残基 ,丝氨酸含量为 10 .6 5 % ,包含 1个连续 32个丝氨酸 (S)残基的序列 ;MSA1基因全长 5 0 85 bp,编码 16 94个氨基酸残基 ,MSA1的氨基酸序列符合 MAD2 0型特征。恶性疟原虫 FCC1/ HN株与 3D7、FC2 7株 GARP的序列差异主要集中于 C-末端 ;FCC1/ HN株与 FCR3、3D7、FCBR、Hondulas- 1株 SERA的序列差异主要集中于 N-端。FCC1/ HN株与MAD2 0、3D7、HN1、HN2、FC2 7、RO- 71、RO- 33、CAMP和 Palo- alto株 MSA1的同源性高 ,K1和 WEL L COME株 MSA1的同源性高 ,各分离株 MSA1的序列差异主要处于第 2至 16分区。 结论 了解了恶性疟原虫 FCC1/ HN株 GARP、SERA和 MSA1的?

Objective To determine the nucleotide sequences of the glutamic acid rich protein(GARP) gene, serine repeat antigen (SERA) gene and merozoite surface antigen 1 (MSA1) gene of Plasmodium falciparum isolate FCC1/HN, and analyze the structure of GARP, SERA and MSA1 of P. falciparum isolate FCC1/HN and sequence diversities of GARP, SERA and MSA1 of different P. falciparum isolates. Methods The fragments of GARP, SERA and MSA1 genes were amplified by PCR from genomic DNA of P. falciparum isolate FCC1/HN and inserted into sequencing vectors and sequenced by dideoxy chain termination method respectively. The DNAstar software were used to analyze the structure of GARP, SERA and MSA1 genes of P. falciparum isolate FCC1/HN and sequence homology of GARP, SERA and MSA1 of different P. falciparum isolates. Results The GARP gene of P. falciparum isolate FCC1/HN was 2 263 base pairs in size, encoding 682 amino acid residues, with 23.61% glutamine residues, including 5 amino acid repeats. The SERA gene of P. falciparum isolate FCC1/HN was 3 448 base pairs in size, encoding 995 amino acid residues, including 10.65% serine residues and a stretch of 32 serine residues. The MSA1 gene of P. falciparum isolate FCC1/HN was 5 085 base pairs in size, encoding 1 694 amino acid residues. The MSA1 of P. falciparum isolate FCC1/HN had the structure character of MAD20 type. The GARP of P. falciparum isolates FCC1/HN, 3D7 and FC27 exhibited amino acid diversities, located mostly in the C terminal region. However, the amino acid diversities of SERA antigens of P. falciparum isolate FCC1/HN, FCR3, 3D7, FCBR and Hondulas 1 located mainly in the N terminal region. The MSA1 of P. falciparum isolate FCC1/HN shared high homology with that of P. falciparum isolate 3D7, MAD20, HN1, HN2, FC27, RO 71, RO 33, CAMP and Palo alto, and the MSA1 of P. falciparum isolate K1 and WELLCOME also shared high homology. The sequence diversities of MSA1 of 12 different P. falciparum isolates above located in the region from block 2 to block 16. Conclusion The primary structure of GARP, SERA and MSA1 and their encoding genes of P. falciparum isolates FCC1/HN were known. The amino acid diversities were located mainly in the specific regions of GARP and SERA of different P. falciparum isolates, and the different blocks of MSA1 of P. falciparum isolate FCC1/HN shared different level of amino acid diversity with those of MSA1 of other P. falciparum isolates.