State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, China.
Virol J. 2011 May 19;8:240. doi: 10.1186/1743-422X-8-240.
RAS, coded by ras proto-oncogenes, played an important role in signal transmission to regulate cell growth and differentiation. Host activation of RAS was significant for IFN-sensitive vaccinia virus (delE3L) or attenuate influenza virus in unallowable cells.
Huamn NRAS gene was activated by mutating in codon 61. Then the activation of NRAS was detected by western blot in MDCK cells. The delNS1 H5N1 influenza virus with deletion of NS1 eIF4GI binding domain was weak multiplication in MDCK cells. And the replication of delNS1 virus and expression of IFN-beta and IRF-3 were detected by Real-time PCR in MDCK cells infected with delNS1 virus. It was found that the delNS1 virus had a significant increase in MDCK cells when the NRAS was activated, and yet, expression of IRF-3 and IFN-beta were restrained.
The study demonstrated that activated NRAS played an important part for delNS1 virus replication in MDCK cells. Activated NRAS might be down-regulating the expression of antiviral cellular factors in delNS1 virus infected cells.
RAS 由 ras 原癌基因编码，在信号转导中发挥重要作用，调节细胞生长和分化。宿主激活 RAS 对 IFN 敏感的牛痘病毒（缺失 E3L）或减毒流感病毒在不允许的细胞中具有重要作用。
HuamnNRAS 基因在密码子 61 处发生突变而被激活。然后通过 Western blot 在 MDCK 细胞中检测到 NRAS 的激活。缺失 NS1 eIF4GI 结合域的 delNS1 H5N1 流感病毒在 MDCK 细胞中复制能力较弱。并通过 Real-timePCR 在感染 delNS1 病毒的 MDCK 细胞中检测到 IFN-β和 IRF-3 的表达。结果发现，当 NRAS 被激活时，delNS1 病毒在 MDCK 细胞中的复制显著增加，而 IRF-3 和 IFN-β 的表达受到抑制。
本研究表明，激活的 NRAS 对 MDCK 细胞中 delNS1 病毒的复制起重要作用。激活的 NRAS 可能下调了 delNS1 病毒感染细胞中抗病毒细胞因子的表达。
