Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
Viruses. 2018 Feb 24;10(2):97. doi: 10.3390/v10020097.
Fowl adenovirus 4 (FAdV-4) is associated with economically important poultry diseases. Recent studies of fully sequenced genomes of FAdV-4 isolates suggest potential genomic regions associated with virulence and amenable for manipulation and vector development. Direct manipulation of viral genomes is cumbersome, as opposed to that of infectious clones-viral genomes cloned into plasmid or cosmid vectors. In this work, we generated an infectious clone, pFAdV-4 ON1, containing the entire viral genome of a nonpathogenic FAdV-4 (ON1 isolate). pFAdV-4 ON1 was used for targeted deletion of open reading frames (ORFs) 16 and 17 and replacement with the enhanced green fluorescence protein (EGFP) expression cassette to generate recombinant viruses. These viruses were viable, and EGFP was expressed in infected cells. Their replication, however, was significantly reduced with respect to that of the wild-type virus. These observations suggest the potential utility of FAdV-4 as a vaccine vector and the importance of ORFs 16 and 17 for virus replication at wild-type levels. To our knowledge, this is the first report of an infectious clone based on the FAdV-4 genome, and our results demonstrate its utility for studies of virulence determinants and as a platform for either vaccine or gene delivery vectors.
禽腺病毒 4 型（FAdV-4）与重要的家禽疾病有关。最近对 FAdV-4 分离株的全序列基因组研究表明，存在与毒力相关的潜在基因组区域，可用于操纵和载体开发。与感染性克隆（克隆到质粒或粘粒载体中的病毒基因组）相比，直接操纵病毒基因组比较繁琐。在这项工作中，我们构建了一个含有非致病性 FAdV-4（ON1 分离株）全长基因组的感染性克隆 pFAdV-4 ON1。pFAdV-4 ON1 用于靶向缺失 ORF16 和 17 并插入增强型绿色荧光蛋白（EGFP）表达盒，以产生重组病毒。这些病毒具有感染性，并且在感染的细胞中表达 EGFP。然而，它们的复制能力与野生型病毒相比显著降低。这些观察结果表明，FAdV-4 作为疫苗载体具有潜在的应用价值，并且 ORF16 和 17 对于病毒在野生型水平的复制非常重要。据我们所知，这是第一个基于 FAdV-4 基因组的感染性克隆的报告，我们的结果表明它可用于研究毒力决定因素，并作为疫苗或基因传递载体的平台。
