An avian leukosis virus subgroup J isolate with a Rous sarcoma virus-like 5′-LTR shows enhanced replication capability
An avian leukosis virus subgroup J isolate with a Rous sarcoma virus-like 5′-LTR shows enhanced replication capability
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DOI：
10.1099/vir.0.071290-0
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发表时间：
2015-01-01
影响因子：
3.8
通讯作者：
Gao, Yulong
中科院分区：
文献类型：
--
作者：
Gao, Yanni;Guan, Xiaolu;Gao, Yulong
禽白血病病毒 J 亚型（ALV-J）首先从患有骨髓性白血病的产肉鸡中分离出来。然而，与血管瘤相关的 ALV-J 感染已发生在中国的产蛋（蛋鸡）鸡群中。在本研究中，我们鉴定出 ALV-J 蛋鸡分离株 (HLJ13SH01) 是 ALV-J 和劳斯肉瘤病毒 Schmidt-Ruppin B 株 (RSV-SRB) 的重组体，其中含有 RSV-SRB 5'-LTR 和 ALV-J 的其他基因。复制动力学测试表明，HLJ13SH01菌株在体外的复制速度比其他ALV-J层分离株更快。序列分析表明，两个分离株之间的主要差异在于5'-LTR序列，特别是U3序列。在 HLJ13SH01 菌株的 U3 区域中独特地发现了 19 nt 插入。 Dual-Glo 荧光素酶测定结果表明，HLJ13SH01 菌株中的 19 nt 插入增加了 U3 区域的增强子活性。此外，在19 nt插入中发现了一个额外的CCAAT/增强子元件，并且荧光素酶测定表明该元件在增加5'-U3区域的增强子活性中发挥了关键作用。为了确认 19 nt 插入和 CCAAT/增强子元件对病毒复制的增强作用，构建并拯救了三个具有 5'-U3 区域变异的感染性克隆。对拯救病毒的复制动力学测试表明，19 nt插入中的CCAAT/增强子元件增强了ALV-J重组体的体外复制能力。
Avian leukosis virus subgroup J (ALV-J) was first isolated from meat-producing chickens that had developed myeloid leukosis. However, ALV-J infections associated with hemangiomas have occurred in egg-producing (layer) flocks in China. In this study, we identified an ALV-J layer isolate (HLJ13SH01) as a recombinant of ALV-J and a Rous sarcoma virus Schmidt-Ruppin B strain (RSV-SRB), which contained the RSV-SRB 5'-LTR and the other genes of ALV-J. Replication kinetic testing indicated that the HLJ13SH01 strain replicated faster than other ALV-J layer isolates in vitro. Sequence analysis indicated that the main difference between the two isolates was the 5'-LTR sequences, particularly the U3 sequences. A 19 nt insertion was uniquely found in the U3 region of the HLJ13SH01 strain. The results of a Dual-Glo luciferase assay revealed that the 19 nt insertion in the HLJ13SH01 strain increased the enhancer activity of the U3 region. Moreover, an additional CCAAT/enhancer element was found in the 19 nt insertion and the luciferase assay indicated that this element played a key role in increasing the enhancer activity of the 5'-U3 region. To confirm the potentiation effect of the 19 nt insertion and the CCAAT/enhancer element on virus replication, three infectious clones with 5'-U3 region variations were constructed and rescued. Replication kinetic testing of the rescued viruses demonstrated that the CCAAT/enhancer element in the 19 nt insertion enhanced the replication capacity of the ALV-J recombinant in vitro.