Smede Matthew, Hussain Mazhar, Asgari Sassan
School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.
Virus Genes. 2009 Dec;39(3):409-17. doi: 10.1007/s11262-009-0407-5. Epub 2009 Oct 10.
A unique feature of ascovirus infection is cleavage of host cells into virus containing vesicles. It has been suggested that the virus induces apoptosis, either by expression of a caspase or other means, which is then diverted toward vesicle formation. There is little known about the mechanism of vesicle formation. Recent genome sequences of three ascoviruses indicated the presence of several putative open reading frames coding for proteins that could be involved in lipid metabolism. These proteins may play a role in rearrangement of membranes in infected host cells leading to formation of vesicles. Here, we analyzed a lipase-like gene (ORF19) from Heliothis virescens ascovirus (HvAV-3e) expressed from 8 h after infection and essential for virus replication and cell cleavage. In addition, ORF19 knock down by RNA interference inhibited virus replication indicating that the gene is indispensable for HvAV-3e replication. However, under enzymatic assays tested, we did not detect any lipase or esterase activity from ORF19.
浓核病毒感染的一个独特特征是将宿主细胞裂解为含有病毒的囊泡。有人提出，病毒通过半胱天冬酶的表达或其他方式诱导细胞凋亡，然后这种凋亡转向囊泡形成。关于囊泡形成的机制知之甚少。最近三种浓核病毒的基因组序列表明，存在几个可能的开放阅读框，编码可能参与脂质代谢的蛋白质。这些蛋白质可能在感染宿主细胞的膜重排中发挥作用，导致囊泡形成。在这里，我们分析了来自棉铃虫浓核病毒（HvAV-3e）的一个类脂肪酶基因（ORF19），该基因在感染后8小时表达，对病毒复制和细胞裂解至关重要。此外，通过RNA干扰敲低ORF19抑制了病毒复制，表明该基因对HvAV-3e复制不可或缺。然而，在测试的酶活性测定中，我们没有检测到ORF19的任何脂肪酶或酯酶活性。
