10月16日,，國(guó)際學(xué)術(shù)期刊Virology在線發(fā)表了中國(guó)科學(xué)院上海巴斯德研究所豐田哲也研究組最新研究成果,，揭示了流感病毒基因組C4啟動(dòng)子/復(fù)制起點(diǎn)具有較弱的聚合酶識(shí)別活性，從而減弱了流感病毒的轉(zhuǎn)錄和復(fù)制,。
流感病毒基因組具有8個(gè)負(fù)鏈RNA片段,。在自然情況下，甲型流感病毒基因組片段3’末端第四位存在U(U4)或C(C4)的變異,。博士研究生蔣紅兵等在豐田哲也的指導(dǎo)下,，通過(guò)深入分析并比較了U4和C4啟動(dòng)子/復(fù)制起點(diǎn)的活性差異，發(fā)現(xiàn)C4的復(fù)制子活性只有U4的28%,。他們利用純化的流感病毒RNA聚合酶在體外分別比較了它以U4 [v84(U4)],、C4 [v84(C4)]和互補(bǔ)RNA鏈（c84）為模板的轉(zhuǎn)錄和復(fù)制活性差異,。實(shí)驗(yàn)結(jié)果表明，無(wú)論是復(fù)制還是轉(zhuǎn)錄,，U4的活性都要比C4高,。進(jìn)一步研究發(fā)現(xiàn)，U4和C4啟動(dòng)子/復(fù)制起點(diǎn)的活性差異主要來(lái)自于聚合酶對(duì)兩種不同的啟動(dòng)子/復(fù)制起點(diǎn)識(shí)別結(jié)合活性差異,。此外,，他們還構(gòu)建了8個(gè)基因組片段全部突變?yōu)閁4或C4啟動(dòng)子/復(fù)制起點(diǎn)的突變體流感病毒，并檢測(cè)了它們?cè)诩?xì)胞內(nèi)的生長(zhǎng)活力差異和在老鼠體內(nèi)的致病力差異,。實(shí)驗(yàn)表明,，U4突變體病毒在細(xì)胞上的生長(zhǎng)活力增強(qiáng)；而C4突變體病毒在細(xì)胞上的生長(zhǎng)活力則減弱了,。但U4或C4突變體病毒在老鼠體內(nèi)的致病性卻都低于野生型WSN病毒,。
上述研究結(jié)果為監(jiān)測(cè)、分析流感病毒的毒力以及制備流感減毒活疫苗提供了新的思路,。
該研究得到了中國(guó)科學(xué)院,、國(guó)家自然科學(xué)基金、李嘉誠(chéng)基金會(huì),、RESPARI項(xiàng)目和歐盟第六框架項(xiàng)目(FLUINNATE)的資助,。（生物谷Bioon.com）
生物谷推薦英文摘要：
Virology doi:10.1016/j.virol.2010.09.022
Influenza virus genome C4 promoter/origin attenuates its transcription and replication activity by the low polymerase recognition activity
Hongbing Jiang1, a, Shijian Zhang1, a, Qiang Wanga, Jinlan Wanga, Liqing Genga and Tetsuya Toyoda, a,
a Unit of Viral Genome Regulation, Institut Pasteur of Shanghai, Key Laboratory of Molecular Virology & Immunology, Chinese Academy of Sciences, 411 Hefei Road, Shanghai 200025, PR China
A natural variation is observed at position 4 of the 3′-end of influenza A virus genomes, where U (U4) or C (C4) is present. The replicon activity of C4 was 28% of U4. We compared the transcription and replication activity of U4 [v84(U4)], C4 [v84(C4)] and the complimentary RNA (c84) using the purified influenza virus RNA polymerase in vitro. ApG-primed replication activities of v84(C4) and c84 were 23.8% and 7.8% of v84(U4). Globin mRNA-primed transcription activities of v84(C4) and c84 were 36.9% and 6.81% of v84(U4). De novo replication activities of v84(C4) and c84 were 21.3 and 10.2% of v84(U4). This difference came from their polymerase binding activity. When all the eight genome segments of WSN strain were changed to U4, the virus titer was 760 times higher than the wild type. However, its pathogenicity in mice was lower than the wild type.
