大鲵 (或称娃娃鱼) 是世界上现存最大的濒危珍稀两栖动物，为我国所特有、被列为国家二级保护野生动物。虹彩病毒在全球范围普遍流行，是侵染众多鱼类、两栖类及爬行类等水生动物的重要病毒病原。有证据表明，虹彩病毒是包括蛙和大鲵在内的两栖类自然种群显著下降或消亡的原因之一，而鉴定虹彩病毒病原并阐明其基因组结构特征是研发相应病害防控技术的前提。
最近，中国科学院水生生物研究所张奇亚研究员、桂建芳研究员和南昌大学洪一江教授联手就大鲵虹彩病毒的全基因组序列及其结构变化开展研究，在新分离鉴定导致大鲵致死性出血病病原——大鲵虹彩病毒 (Andrias davidianus ranaviurs， ADRV) 的基础上，测定了其全基因组序列，并与已知两栖类蛙虹彩病毒基因组进行点阵及结构变化分析。结果显示，ADRV基因组全长为106，734 bp，可编码101个开放阅读框，其中含虹彩病毒家族26个核心基因、蛙病毒属成员24个特有基因及两栖类蛙病毒亚属的11个特有基因；发现几个涉及病毒毒力及宿主感染性的关键基因发生显著变化。进而指出，在大鲵虹彩病毒基因组中有明显变化的这些基因可在削弱或改变宿主抗病力、增强ADRV致病性以及跨种传播中起关键作用。该研究不仅首次揭示导致大鲵自然种群衰减与养殖群体疾病频发的虹彩病毒分子特征，也为深入了解这类病毒流行和基因组进化规律、以及研发两栖类病毒病免疫防控技术提供了新的研究思路。
该研究得到国家基础研究973计划和自然科学基金等项目资助。研究论文“Genome architecture changes and major gene variations of Andrias davidianus ranavirus (ADRV)”于近日在Veterinary Research (兽医学科1/142) 在线发表，第一作者为陈中元博士，通讯作者为张奇亚研究员。（生物谷Bioon.com）
生物谷推荐的英文摘要
Veterinary Research doi:10.1186/1297-9716-44-101
Genome architecture changes and major gene variations of Andrias davidianus ranavirus (ADRV)
Zhongyuan Chen， Jianfang Gui， Xiaochan Gao， Chao Pei， Yijiang Hong and Qiya Zhang
Ranaviruses are emerging pathogens that have led to global impact and public concern. As a rarely endangered species and the largest amphibian in the world， the Chinese giant salamander， Andrias davidianus， has recently undergone outbreaks of epidemic diseases with high mortality. In this study， we isolated and identified a novel ranavirus from the Chinese giant salamanders that exhibited systemic hemorrhage and swelling syndrome with high death rate in China during May 2011 to August 2012. The isolate， designated Andrias davidianus ranavirus (ADRV)， not only could induce cytopathic effects in different fish cell lines and yield high viral titers， but also caused severely hemorrhagic lesions and resulted in 100% mortality in experimental infections of salamanders. The complete genome of ADRV was sequenced and compared with other sequenced amphibian ranaviruses. Gene content and phylogenetic analyses revealed that ADRV should belong to an amphibian subgroup in genus Ranavirus， and is more closely related to frog ranaviruses than to other salamander ranaviruses. Homologous gene comparisons show that ADRV contains 99%， 97%， 94%， 93% and 85% homologues in RGV， FV3， CMTV， TFV and ATV genomes respectively. In addition， several variable major genes， such as duplicate US22 family-like genes， viral eukaryotic translation initiation factor 2 alpha gene and novel 75L gene with both motifs of nuclear localization signal (NLS) and nuclear export signal (NES)， were predicted to contribute to pathogen virulence and host susceptibility. These findings confirm the etiologic role of ADRV in epidemic diseases of Chinese giant salamanders， and broaden our understanding of evolutionary emergence of ranaviruses.
