Fukushi Noriko, Badr Yassien, Fukushi Hideto
Department of Applied Veterinary Sciences, United Graduated School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Department of Animal Medicine (Branch of Infectious Disease), Faculty of Veterinary Medicine, Damanhour University, El-Beheira 2251, Egypt.
J Gen Virol. 2023 Jan;104(1). doi: 10.1099/jgv.0.001798.
Equine herpesvirus type 1 (EHV-1) UL11 is a 74-amino-acid (aa) protein encoded by ORF51. UL11 is modified by acylation including myristoylation and palmitoylation. Myristoylation of EHV-1 UL11 is assumed to occur on the N-terminal glycine, while palmitoylation is assumed to occur on the seventh and ninth cysteines. ORF51, which encodes the first 24 aa, overlaps ORF50 encoding UL12. We previously demonstrated that UL11 was essential for EHV-1 replication in cultured cells and that UL11 was localized at the Golgi apparatus where herpesviruses obtain their final envelope. It is unclear whether the acylation is related to the localization of EHV-1 UL11 and viral replication. In this study, we investigated the role of UL11 acylation in the intracellular localization and viral growth and replication of EHV-1. We constructed seven UL11 acylation mutant plasmids and seven UL11 acylation mutant BAC DNAs; then, we analysed the localizations of the mutant UL11s and attempted virus rescue. We found that both the N-terminal glycine and the seventh or ninth cysteine, especially N-terminal glycine, were involved in the localization of UL11 and viral replication. Taken together, these results suggest that EHV-1 viral growth requires that UL11 is modified by myristoylation of an N-terminal glycine and by palmitoylation of at least one of the cysteines, and that UL11 is localized at the Golgi apparatus. This study shows that a single amino acid in EHV-1 can determine the fate of viral replication.
1型马疱疹病毒（EHV-1）的UL11是由开放阅读框51（ORF51）编码的一种含74个氨基酸（aa）的蛋白质。UL11通过酰化修饰，包括肉豆蔻酰化和棕榈酰化。EHV-1 UL11的肉豆蔻酰化被认为发生在N端甘氨酸上，而棕榈酰化被认为发生在第7和第9个半胱氨酸上。编码前24个氨基酸的ORF51与编码UL12的ORF50重叠。我们之前证明，UL11对EHV-1在培养细胞中的复制至关重要，并且UL11定位于疱疹病毒获得其最终包膜的高尔基体。目前尚不清楚酰化是否与EHV-1 UL11的定位及病毒复制有关。在本研究中，我们调查了UL11酰化在EHV-1细胞内定位及病毒生长和复制中的作用。我们构建了7个UL11酰化突变体质粒和7个UL11酰化突变体细菌人工染色体（BAC）DNA；然后，我们分析了突变型UL11的定位并尝试进行病毒拯救。我们发现，N端甘氨酸以及第7或第9个半胱氨酸，尤其是N端甘氨酸，参与了UL11的定位和病毒复制。综上所述，这些结果表明，EHV-1病毒生长需要UL11通过N端甘氨酸的肉豆蔻酰化以及至少一个半胱氨酸的棕榈酰化进行修饰，并且UL11定位于高尔基体。本研究表明，EHV-1中的单个氨基酸可以决定病毒复制的命运。
