Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue road, Shanghai, 200241, PR China.
Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Shandong Agricultural University, Taian, Shandong, 271018, PR China.
Vet Microbiol. 2018 Feb;214:21-27. doi: 10.1016/j.vetmic.2017.12.002. Epub 2017 Dec 6.
Duck circovirus (DuCV) is divided into genotypes 1 and 2. The DuCV ORF3 protein is a newly identified viral protein with apoptotic activity. In this study, the differences in the gene sequences, subcellular localization, and apoptotic activities of the ORF3 proteins of DuCV genotypes 1 and 2 were analyzed. A T-to-A point mutation at nucleotide 236 (T236A) in the ORF3 gene sequence of DuCV genotype 1 was observed, which generates a premature stop codon (TAG) and resulted in a truncated ORF3 protein. The ORF3 protein of DuCV genotype 2 is 20 amino acids longer at its C-terminus than the truncated ORF3 protein of genotype 1. A variant monopartite-type nuclear localization signal (RRLRTCNCRACRTLK) was identified within the C-terminal region of the ORF3 protein of DuCV genotype 2, which is essential for the nuclear localization of the protein. The 20 C-terminal residues of the DuCV genotype 2 ORF3 protein also inhibits the apoptotic activity of the protein. Our findings provide insight into the biological and functional characteristics of the DuCV ORF3 protein.
鸭圆环病毒（DuCV）分为 1 型和 2 型。DuCV ORF3 蛋白是一种新发现的具有凋亡活性的病毒蛋白。本研究分析了 1 型和 2 型 DuCV ORF3 蛋白在基因序列、亚细胞定位和凋亡活性方面的差异。在 1 型 DuCV ORF3 基因序列中观察到核苷酸 236 处（T236A）的 T 到 A 点突变，产生一个过早的终止密码子（TAG），导致 ORF3 蛋白截短。2 型 DuCV 的 ORF3 蛋白在 C 末端比 1 型的截短 ORF3 蛋白长 20 个氨基酸。在 2 型 DuCV ORF3 蛋白的 C 末端区域鉴定出一种变体单份型核定位信号（RRLRTCNCRACRTLK），这对于蛋白质的核定位是必需的。DuCV 基因型 2 的 ORF3 蛋白的 20 个 C 末端残基也抑制了该蛋白的凋亡活性。我们的研究结果提供了对 DuCV ORF3 蛋白生物学和功能特性的深入了解。
