Ewing Sean G, Byrd Serena A, Christensen Joan B, Tyler Ryan E, Imperiale Michael J
Department of Microbiology and Immunology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
J Virol. 2007 Nov;81(22):12450-7. doi: 10.1128/JVI.01470-07. Epub 2007 Sep 5.
Assembly of infectious adenovirus particles requires seven functionally redundant elements at the left end of the genome, termed A repeats, that direct packaging of the DNA. Previous studies revealed that the viral IVa2 protein alone interacts with specific sequences in the A repeats but that additional IVa2-containing complexes observed during infection require the viral L4 22-kDa protein. In this report, we purified a recombinant form of the 22-kDa protein to characterize its DNA binding properties. In electrophoretic mobility shift assay analyses, the 22-kDa protein alone did not interact with the A repeats but it did form complexes on them in the presence of the IVa2 protein. These complexes were identical to those seen in extracts from infected cells and had the same DNA sequence dependence. Furthermore, we provide data that the 22-kDa protein enhances binding of the IVa2 protein to the A repeats and that multiple binding sites in the packaging sequence augment this activity. These data support a cooperative role of the IVa2 and 22-kDa proteins in packaging and assembly.
感染性腺病毒颗粒的组装需要基因组左端的七个功能冗余元件，称为A重复序列，它们指导DNA的包装。先前的研究表明，单独的病毒IVa2蛋白与A重复序列中的特定序列相互作用，但在感染过程中观察到的其他含IVa2的复合物需要病毒L4 22 kDa蛋白。在本报告中，我们纯化了重组形式的22 kDa蛋白以表征其DNA结合特性。在电泳迁移率变动分析中，单独的22 kDa蛋白不与A重复序列相互作用，但在IVa2蛋白存在的情况下，它确实在A重复序列上形成复合物。这些复合物与感染细胞提取物中看到的复合物相同，并且具有相同的DNA序列依赖性。此外，我们提供的数据表明，22 kDa蛋白增强了IVa2蛋白与A重复序列的结合，并且包装序列中的多个结合位点增强了这种活性。这些数据支持IVa2和22 kDa蛋白在包装和组装中的协同作用。
