Liu Fang-Lin, Chang Shu-Ping, Liu Hung-Jen, Liu Pan-Chen, Wang Chi-Young
Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, 145 Xingda Road, Taichung 402, Taiwan.
Department of Laboratory, Chang Bing Show Chwan Memorial Hospital, 6 Lugong Road, Changhua, Lugang, Taiwan.
Virus Res. 2022 Jan 15;308:198634. doi: 10.1016/j.virusres.2021.198634. Epub 2021 Nov 15.
Avian polyomavirus (APV) is a non-enveloped virus with a circular double-stranded DNA genome approximately 5000 bp in length. APV was first reported in fledgling budgerigars (Melopsittacus undulatus) as the causative agent of budgerigar fledgling disease, resulting in high parrot mortality rates in the 1980s. This disease has been observed worldwide, and APV has a wide host range including budgerigars, cockatoos, lorikeets, lovebirds, and macaws. Twenty APV isolates have been collected from healthy and symptomatic parrots in Taiwan from 2015 to 2019. These isolates were then amplified via polymerase chain reaction, after which the whole genomes of these isolates were sequenced. The overall APV-positive rate was 14.2%, and the full lengths of the APV Taiwan isolates varied from 4971 to 4982 bps. The APV genome contains an early region that encodes two regulatory proteins (the large tumor antigen (Large T-Ag) and the small tumor antigen (Small t-Ag)) and a late region which encodes the capsid proteins VP1, VP2, VP3, and VP4. The nucleotide identities of the VP1 and VP4 genes ranged from 98.7 to 100%, whereas the nucleotide sequence of the Large T-Ag gene had the highest identity (99.2-100%) relative to other APV isolates from the GenBank database. A phylogenetic tree based on the whole genome demonstrated that the APV Taiwan isolates were closely related to Japanese and Portuguese isolates. Recombination events were analyzed using the Recombination Detection Program version 4 and APV Taiwan isolate TW-3 was identified as a minor parent of the APV recombinants. In this study, we first reported the characterization of the whole genome sequences of APV Taiwan isolates and their phylogenetic relationships with all APV isolates available in the GenBank database.
禽多瘤病毒（APV）是一种无包膜病毒，其环状双链DNA基因组长度约为5000碱基对。APV最早在雏虎皮鹦鹉（虎皮鹦鹉）中被报道为虎皮鹦鹉雏鸟病的病原体，在20世纪80年代导致鹦鹉的高死亡率。这种疾病在全球范围内都有观察到，APV的宿主范围很广，包括虎皮鹦鹉、凤头鹦鹉、吸蜜鹦鹉、情侣鹦鹉和金刚鹦鹉。2015年至2019年期间，从台湾健康和有症状的鹦鹉中收集了20株APV分离株。然后通过聚合酶链反应对这些分离株进行扩增，之后对这些分离株的全基因组进行测序。APV的总体阳性率为14.2%，台湾APV分离株的全长在4971至4982碱基对之间变化。APV基因组包含一个早期区域，编码两种调节蛋白（大肿瘤抗原（大T抗原）和小肿瘤抗原（小t抗原））和一个晚期区域，编码衣壳蛋白VP1、VP2、VP3和VP4。VP1和VP4基因的核苷酸同一性在98.7%至100%之间，而大T抗原基因的核苷酸序列与GenBank数据库中其他APV分离株相比具有最高的同一性（99.2 - 100%）。基于全基因组构建的系统发育树表明，台湾APV分离株与日本和葡萄牙的分离株密切相关。使用重组检测程序版本4分析重组事件，台湾APV分离株TW - 3被鉴定为APV重组体的次要亲本。在本研究中，我们首次报道了台湾APV分离株全基因组序列的特征及其与GenBank数据库中所有可用APV分离株的系统发育关系。
