腺病毒7d基因型与7b基因型全基因组比较分析

Comparative Genomics of Human Adenovirus 7d and 7b

为了解重庆地区流行的7型腺病毒(Human adenovirus 7,HAdV-7)基因型型别,从全基因组水平探讨HAdV-7b和HAdV-7d可能的致病性差异,收集儿童急性下呼吸道感染患儿的呼吸道分泌物标本分离培养,提取DNA后进行HAdV-7基因型别鉴定、限制性酶切分析和全基因组测序,再利用MEGA6比较分析。本研究在2009年6月~2013年1月间共收集4334份急性下呼吸道感染患儿的鼻咽抽吸物标本,随机选取2411份进行病毒分离培养,共有164份(164/2411,6.8%)鼻咽抽吸物HAdV阳性,其中HAdV-7 87例。限制性酶切分析显示,随机挑选的3株HAdV-7分离株均为HAdV-7d。CQ1198株行全基因组测序并与其他HAdV-7全基因组构建进化树,结果发现16株中国地区的HAdV-7为HAdV-7d基因型,且上述16株HAdV-7与7d2的同源性为99.9%,与7b的同源性为98.2%。相较于ak40株(HAdV-7b),CQ1198共有49处核苷酸替换,其中20处可导致非同义替换;4处核苷酸插入,其中24bp和18bp 2个片段插入分别位于病毒相关RNAⅡ(Virus-associated RNAⅡ,VA RNAⅡ)和L3的pⅥ区域。HAdV-7可有多个基因型致病,且一直处于进化过程中,其主要流行基因型由HAdV-7b变为HAdV-7d。应加强对HAdV分子流行病学监测,明确其进化规律,为HAdV疫苗研发提供分子流行病学依据。

To genotype the HAdV-7strains circulating in Chongqing,and conduct genetic diversity analyses on the whole-genome sequences of HAdV-7dand HAdV-7b.A total of 4334 nasopharyngeal aspirates（NPAs）were collected from June 2009 to January 2011,and 2411 NPAs were selected to undergo isolation.A total of 164NPAs（164/2411）6.8% were positive for HAdV,and HAdV-7was detected in 87 cases.Restriction endonuclease analyses showed that the genotype of the three HAdV-7strains selected randomly was HAdV-7d.Phylogenetic analyses showed that the 16 HAdV-7strains in China including the Chongqing strain CQ1198 were clustered into the HAdV-7dgenotype,and shared a similarity of 99.9%and 98.2% with 7d2 and 7bgenotypes,respectively.There were 49 nucleotide substitutions in CQ1198 compared with ak40,including 20 nonsynonymous substitutions,and four insertions.The insertions occurred in virus-associated RNA IIand pVI separately.In summary,there are multiple genotypes in HAdV-7,and the genotypes of HAdV-7bshifted to HAdV-7din China during continuous evolution of the virus.Continuous surveillance of the evolution of this virus will provide evidence for vaccine research and avoidance of epidemics.