Distinct roles of the adenovirus E4 ORF3 protein in viral DNA replication and inhibition of genome concatenation
Distinct roles of the adenovirus E4 ORF3 protein in viral DNA replication and inhibition of genome concatenation
复制标题
DOI：
10.1128/jvi.77.9.5295-5304.2003
复制
发表时间：
2003-05-01
影响因子：
5.4
通讯作者：
Hearing, P
中科院分区：
文献类型：
--
作者：
Evans, JD;Hearing, P
腺病毒早期蛋白E4 ORF3和E4 ORF6在病毒感染过程中具有互补功能。这两种蛋白都能促进高效的病毒DNA复制、晚期蛋白表达和防止病毒基因组的连接。此外，E4 ORF6通过与E1B 55K蛋白的相互作用参与关闭宿主细胞蛋白合成。这种复合物也会导致p53的降解。E4 ORF3的一个独特功能是重组被称为PML致癌结构域（PODS）的核结构。这些结构域的功能尚不清楚，但pod参与了许多重要的细胞过程，包括转录调节、凋亡、转化和对干扰素的反应。本研究的目的是确定E4 ORF3重组pod的功能意义。E4 ORF3基因发生点突变。这些突变体被重组成缺乏E4 ORF6的病毒，并在天然病毒E4启动子的控制下表达。突变病毒组用于研究E4 ORF3在病毒感染过程中的作用。其中一种突变病毒pod重组异常，病毒DNA复制存在严重缺陷，导致病毒产量急剧下降。许多突变体积累了病毒DNA和传染性病毒颗粒，达到野生型水平，但表现出显著的病毒基因组串联。这些数据表明E4 ORF3是一种多功能蛋白，核PML结构域的特异性重排与有效的病毒DNA复制有关。这种功能不同于E4 ORF3通过抑制细胞双链断裂修复来调节病毒基因组连接的作用。
Adenovirus early proteins E4 ORF3 and E4 ORF6 have complementary functions during viral infection. Both proteins facilitate efficient viral DNA replication, late protein expression, and prevention of concatenation of viral genomes. Additionally, E4 ORF6 is involved in the shutoff of the host cell protein synthesis through its interaction with the E1B 55K protein. This complex also leads to the degradation of p53. A unique function of E4 ORF3 is the reorganization of nuclear structures known as PML oncogenic domains (PODS). The function of these domains is unclear, but PODS have been implicated in a number of important cellular processes, including transcriptional regulation, apoptosis, transformation, and response to interferon. The goal of this study was to determine the functional significance of the reorganization of PODS by E4 ORF3. Point mutations were made in the E4 ORF3 gene. These mutants were recombined into a virus lacking E4 ORF6 and expressed under the control of the natural virus E4 promoter. The panel of mutant viruses was used to investigate the role of E4 ORF3 during the course of the viral infection program. One of the mutant viruses exhibited aberrant reorganization of PODS and had a severe defect in viral DNA replication, thus leading to a dramatic decrease in virus production. A number of mutants accumulated viral DNA and infectious virus particles to wild-type levels but showed significant viral genome concatenation. These data show that E4 ORF3 is a multifunctional protein and that a specific rearrangement of nuclear PML domains is coupled to efficient viral DNA replication. This function is distinct from the role of E4 ORF3 in the regulation of virus genome concatenation via inhibition of cellular double-strand break repair.