SARS(severe acute respiratory syndrome)冠状病毒已被世界卫生组织确认为SARS传染病的病原体,它的全基因组测序工作分别由中国、加拿大、美国等国的研究小组完成。然而它的起源仍是一个谜为了探寻SARS冠状病毒的来源,基于FDOD(function of degree of disagreement)方法,对12个SARS冠状病毒分离株和12种以往发现的冠状病毒进行了全基因组比较,构造出种系进化无根树。结果表明,这两类病毒(分别由12个SARS冠状病毒分离株和12种以往发现的冠状病毒构成)虽然都来自冠状病毒属,但它们位于两个不同的进化分支上。冠状病毒属中的3个组被准确地重构。根据得到的结果,推测SARS冠状病毒更类似于第一组中的冠状病毒。根据种系进化树的拓扑结构和各SARS冠状病毒分离株与造成香港Metropole饭店疫情的SARS冠状病毒株之间的联系,推测各SARS冠状病毒分离株分别位于进化树上两个大的分支,这为SARS的流行病学研究提供了辅助信息。
Here we report the codon bias and the mRNA secondary structural features of the hemagglutinin(HA)cleavage site basic amino acid regions of avian influenza virus H5N1 subtypes.We have developed a dynamic extended folding strategy to predict RNA secondary structure with RNAstructure 4.1 program in an iterative extension process.Statistical analysis of the sequences showed that the HA cleavage site basic amino acids favor the adenine-rich codons,and the corresponding mRNA fragments are mainly in the folding states of single-stranded loops.Our sequential and structural analyses showed that to prevent and control these highly pathogenic viruses,that is,to inhibit the gene expression of avian influenza virus H5N1 subtypes,we should consider the single-stranded loop regions of the HA cleavage site-coding sequences as the targets of RNA interference.
