大鯢 (或稱娃娃魚) 是世界上現(xiàn)存最大的瀕危珍稀兩棲動(dòng)物，為我國(guó)所特有,、被列為國(guó)家二級(jí)保護(hù)野生動(dòng)物,。虹彩病毒在全球范圍普遍流行，是侵染眾多魚類,、兩棲類及爬行類等水生動(dòng)物的重要病毒病原,。有證據(jù)表明，虹彩病毒是包括蛙和大鯢在內(nèi)的兩棲類自然種群顯著下降或消亡的原因之一,，而鑒定虹彩病毒病原并闡明其基因組結(jié)構(gòu)特征是研發(fā)相應(yīng)病害防控技術(shù)的前提,。
最近，中國(guó)科學(xué)院水生生物研究所張奇亞研究員,、桂建芳研究員和南昌大學(xué)洪一江教授聯(lián)手就大鯢虹彩病毒的全基因組序列及其結(jié)構(gòu)變化開展研究,，在新分離鑒定導(dǎo)致大鯢致死性出血病病原——大鯢虹彩病毒 (Andrias davidianus ranaviurs， ADRV) 的基礎(chǔ)上,，測(cè)定了其全基因組序列,，并與已知兩棲類蛙虹彩病毒基因組進(jìn)行點(diǎn)陣及結(jié)構(gòu)變化分析。結(jié)果顯示,，ADRV基因組全長(zhǎng)為106,，734 bp，可編碼101個(gè)開放閱讀框,，其中含虹彩病毒家族26個(gè)核心基因,、蛙病毒屬成員24個(gè)特有基因及兩棲類蛙病毒亞屬的11個(gè)特有基因；發(fā)現(xiàn)幾個(gè)涉及病毒毒力及宿主感染性的關(guān)鍵基因發(fā)生顯著變化,。進(jìn)而指出,，在大鯢虹彩病毒基因組中有明顯變化的這些基因可在削弱或改變宿主抗病力、增強(qiáng)ADRV致病性以及跨種傳播中起關(guān)鍵作用,。該研究不僅首次揭示導(dǎo)致大鯢自然種群衰減與養(yǎng)殖群體疾病頻發(fā)的虹彩病毒分子特征,，也為深入了解這類病毒流行和基因組進(jìn)化規(guī)律、以及研發(fā)兩棲類病毒病免疫防控技術(shù)提供了新的研究思路,。
該研究得到國(guó)家基礎(chǔ)研究973計(jì)劃和自然科學(xué)基金等項(xiàng)目資助,。研究論文“Genome architecture changes and major gene variations of Andrias davidianus ranavirus (ADRV)”于近日在Veterinary Research (獸醫(yī)學(xué)科1/142) 在線發(fā)表,，第一作者為陳中元博士,，通訊作者為張奇亞研究員。（生物谷Bioon.com）
生物谷推薦的英文摘要
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.
