Timely Synthesis of the Adenovirus Type 5 E1B 55-Kilodalton Protein Is Required for Efficient Genome Replication in Normal Human Cells
Timely Synthesis of the Adenovirus Type 5 E1B 55-Kilodalton Protein Is Required for Efficient Genome Replication in Normal Human Cells
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DOI：
10.1128/jvi.06764-11
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发表时间：
2012-03-01
影响因子：
5.4
通讯作者：
Flint, S. J.
中科院分区：
文献类型：
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作者：
Chahal, Jasdave S.;Flint, S. J.
以前的研究表明，腺病毒5型E1 B 55-kDa蛋白促进病毒DNA合成在正常人包皮成纤维细胞（HFF），但不是在原代上皮细胞。为了进一步研究这种明显的差异，在原代人成纤维细胞和上皮细胞感染的突变体AdEasyE 1德尔塔2347，它携带的Hr 6移码突变，防止生产的E1 B 55 kDa蛋白，在E1-含衍生物的AdEasy病毒DNA积累进行了检查。在正常HFF中观察到病毒DNA合成受损，但在被该突变体感染的正常人支气管上皮细胞中未观察到。然而，通过早期阶段的进展，这是显着慢于上皮细胞中的HFF的加速，消除了依赖于E1 B 55-kDa蛋白的HFF中的有效的病毒DNA合成。这些观察结果表明，E1 B 55 kDa蛋白的及时合成保护正常细胞免受抑制腺病毒基因组复制的宿主防御。一种这样的防御是由Mre 11-Rad 50-Nbs 1复合物介导的。然而，通过免疫荧光检测Mre 11和病毒蛋白的定位表明，该复合物在AdEasyE 1 Delta 2347突变体感染和AdEasyE 1感染的HFF中失活相似。
Previous studies have indicated that the adenovirus type 5 E1B 55-kDa protein facilitates viral DNA synthesis in normal human foreskin fibroblasts (HFFs) but not in primary epithelial cells. To investigate this apparent difference further, viral DNA accumulation was examined in primary human fibroblasts and epithelial cells infected by the mutant AdEasyE1 Delta 2347, which carries the Hr6 frameshift mutation that prevents production of the E1B 55-kDa protein, in an E1-containing derivative of AdEasy. Impaired viral DNA synthesis was observed in normal HFFs but not in normal human bronchial epithelial cells infected by this mutant. However, acceleration of progression through the early phase, which is significantly slower in HFFs than in epithelial cells, eliminated the dependence of efficient viral DNA synthesis in HFFs on the E1B 55-kDa protein. These observations suggest that timely synthesis of the E1B 55-kDa protein protects normal cells against a host defense that inhibits adenoviral genome replication. One such defense is mediated by the Mre11-Rad50-Nbs1 complex. Nevertheless, examination of the localization of Mre11 and viral proteins by immunofluorescence suggested that this complex is inactivated similarly in AdEasyE1 Delta 2347 mutant-infected and AdEasyE1-infected HFFs.