The N Terminus of Autographa californica Multiple Nucleopolyhedrovirus DNA Polymerase Is Required for Efficient Viral DNA Replication and Virus and Occlusion Body Production

文献类型： 外文期刊

第一作者： Chen, Guoqing

作者： Chen, Guoqing;Yan, Qing;Fang, Yang;Wu, Lijuan;Feng, Guozhong;Krell, Peter J.

作者机构：

关键词： DNA polymerase; DNA replication; N terminus; baculovirus; dsDNA virus

期刊名称：JOURNAL OF VIROLOGY （ 影响因子：5.103； 五年影响因子：5.078 ）

ISSN： 0022-538X

年卷期： 2018 年 92 卷 11 期

页码：

收录情况： SCI

摘要： Autographa californica multiple nucleopolyhedrovirus (AcMNPV) DNA polymerase (DNApol) plays a crucial role in viral DNA synthesis, and the N terminus (residues 1 to 186) is highly conserved in the baculovirus DNApol family. However, the functional role of the N terminus of DNApol has not yet been characterized. Here we report a functional analysis of the AcMNPV DNApol N terminus. We truncated the DNApol N terminus to construct truncation mutants Bac-GFP-Pol.64, Bac-GFP-Pol Delta 110, and Bac-GFP-Pol Delta 186, which lack 64, 110, and 186 N-terminal residues, respectively. Although the truncation mutants rescued viral DNA synthesis and infectious virus production, the level of DNA replication decreased, and Bac-GFP-Pol Delta 64, Bac-GFP-Pol Delta 110, and Bac-GFP-Pol Delta 186 showed 10-fold, 89-fold, and 891-fold reductions in infectious viral yield compared to that of the wild-type repair virus, respectively. Production of occlusion bodies was compromised for all truncation mutants. Further bioinformatic analysis showed that the first 64 amino acids (aa) at the extreme N terminus contains a conserved alpha(-helix)-beta(-sheet)-beta-beta secondary-structure region, and further downstream sequence from aa 67 to 186 is comprised of four conserved sequence motifs. Multiple alanine point substitutions in the alpha-beta-beta-beta structure region or the four sequence motifs in the N terminus impaired viral DNA replication and resulted in reduction of virus yield and occlusion body production. Together, our results suggested that the secondary structure and four conserved motifs within the N terminus of AcMNPV DNApol are important for viral DNA synthesis, infectious virus yield, and production of occlusion bodies. IMPORTANCE DNA polymerase (DNApol) is highly conserved in all baculoviruses and is required for viral DNA replication. The N terminus is one of the highly conserved regions of baculovirus DNApols. Our results showed that the N terminus of baculovirus DNA polymerase plays an important role in efficient viral DNA synthesis and infectious virus yield and production of occlusion bodies. We identified five features, including a highly conserved secondary structure and four conserved amino acid motifs, in the AcMNPV DNApol N terminus, all of which are important for efficient viral DNA synthesis, infectious virus yield, and production of occlusion bodies.

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