Ayalew Lisanework E, Patel Amrutlal K, Gaba Amit, Islam Azharul, Tikoo Suresh K
Vaccine and Infectious Disease Organization - International Vaccine Centre, University of Saskatchewan, Saskatoon, SKCanada; Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SKCanada.
Vaccine and Infectious Disease Organization - International Vaccine Centre, University of Saskatchewan, Saskatoon, SK Canada.
Front Microbiol. 2016 Dec 27;7:2119. doi: 10.3389/fmicb.2016.02119. eCollection 2016.
Earlier, targeting of DDX3 by few viral proteins has defined its role in mRNA transport and induction of interferon production. This study was conducted to investigate the function of bovine adenovirus (BAdV)-3 pVIII during virus infection. Here, we provided evidence regarding involvement of DDX3 in cap dependent cellular mRNA translation and demonstrated that targeting of DDX3 by adenovirus protein VIII interfered with cap-dependent mRNA translation function of DDX3 in virus infected cells. Adenovirus late protein pVIII interacted with DDX3 in transfected and BAdV-3 infected cells. pVIII inhibited capped mRNA translation and by limiting the amount of DDX3 and eIF3. Diminished amount of DDX3 and eIFs including eIF3, eIF4E, eIF4G, and PABP were present in cap binding complex in BAdV-3 infected or pVIII transfected cells with no trace of pVIII in cap binding complex. The total amount of eIFs appeared similar in uninfected or infected cells as BAdV-3 did not appear to degrade eIFs. The co-immunoprecipitation experiments indicated the absence of direct interaction between pVIII and eIF3, eIF4E, or PABP. These data indicate that interaction of pVIII with DDX3 interferes with the binding of eIF3, eIF4E and PABP to the 5' Cap. We conclude that DDX3 promotes cap-dependent cellular mRNA translation and BAdV-3 pVIII inhibits translation of capped cellular mRNA possibly by interfering with the recruitment of eIFs to the capped cellular mRNA.
此前，几种病毒蛋白对DDX3的靶向作用已明确了其在mRNA转运和干扰素产生诱导中的作用。本研究旨在调查牛腺病毒（BAdV）-3 pVIII在病毒感染过程中的功能。在此，我们提供了关于DDX3参与帽依赖性细胞mRNA翻译的证据，并证明腺病毒蛋白VIII对DDX3的靶向作用会干扰病毒感染细胞中DDX3的帽依赖性mRNA翻译功能。腺病毒晚期蛋白pVIII在转染细胞和BAdV-3感染细胞中与DDX3相互作用。pVIII通过限制DDX3和eIF3的量来抑制带帽mRNA的翻译。在BAdV-3感染或pVIII转染的细胞中，帽结合复合物中DDX3和包括eIF3、eIF4E、eIF4G和PABP在内的eIFs数量减少，而帽结合复合物中没有pVIII的踪迹。未感染或感染细胞中eIFs的总量似乎相似，因为BAdV-3似乎不会降解eIFs。免疫共沉淀实验表明pVIII与eIF3、eIF4E或PABP之间不存在直接相互作用。这些数据表明pVIII与DDX3的相互作用会干扰eIF3、eIF4E和PABP与5'帽的结合。我们得出结论，DDX3促进帽依赖性细胞mRNA翻译，而BAdV-3 pVIII可能通过干扰eIFs募集到带帽细胞mRNA上而抑制带帽细胞mRNA的翻译。
