北京地区传播的SARS冠状病毒N区基因变异分析

Variation Analysis of Nucleocapsid Gene of SARS Coronavirus Transmitted in Beijing Area

SARS冠状病毒的N蛋白具有很强的免疫原性 ,是机体产生特异性体液反应主要针对的靶分子之一。收集并提取了我院收治的北京地区 1 2位确诊SARS患者的病毒RNA样本 ,用反转录巢式聚合酶链式反应分 3个片段扩增出N基因全序列 ,用pGEM T载体克隆后进行DNA序列分析。结果发现 ,在 1 2条病毒N基因序列中 ,与北京地区最早报告的BJ0 1株SARS冠状病毒N基因序列相比 ,有 3个核苷酸替换 ,分布于 2个序列位点 ,分别为 2 841 7G→C(aa1 0 6S→T)和 2 8433C→T(aa1 1 1F→F同义突变 ) ,均为新发现的变异位点。结果表明 ,北京地区传播的SARS冠状病毒N基因存在变异序列 ,但发生频率较低 ,提示N基因的结构稳定对病毒的生存较为重要。

Nucleocapsid (N) protein of SARS coronavirus (SARS-CoV) with dominent immunogenicity to induce host humoral immunity was characterized. Samples from 12 patients with confirmed SARS hospitalized on our unit were employed for N gene sequence analysis. The samples included 5 of plasma, 6 of sputum and 1 of stool. The viral RNA was isolated directly from the samples. Nested RT-PCR was performed to amplify the N gene of viral genome using 3 groups of specific primers. The amplified products were cloned into pGEM-T vector for DNA sequence analysis. The nucleotide replacements distributing in 2 sequence sites were identified from 2 of 12 full-length N gene sequences in comparison with BJ01 SARS-CoV strain. They were one at position 28417 (G→C, aa106 S→T) and two at position 28433 (C→T, aa111 F→F). Both variation sequence sites have not been documented before. The results suggested that though variation exists in the N gene of SARS-CoV, the frequency is relatively lower. Therefore, the stability of N protein is important for maintenance of SARS-CoV bioactivity. ;