Hamajima Rina, Kobayashi Michihiro, Ikeda Motoko
Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
Virology. 2015 Nov;485:244-51. doi: 10.1016/j.virol.2015.08.008. Epub 2015 Aug 25.
We previously demonstrated that rRNA undergoes rapid and extensive degradation in Bombyx mori BM-N cells upon infection with AcMNPV, which is triggered by AcMNPV P143 (Ac-P143) protein. Here, we showed that six amino acid residues of Ac-P143 protein, distributing between positions 514 and 599, are involved in rRNA degradation in BM-N cells. The six residues are highly conserved among P143 proteins from AcMNPV, HycuMNPV, SeMNPV and SpltMNPV, which trigger rRNA degradation in BM-N cells upon infection, but are only partially conserved in Bm-P143 protein, which does not induce rRNA degradation in BM-N cells. We also demonstrated that substitution of only two selected residues (N565S/L578F) of Bm-P143 protein with the corresponding Ac-P143 protein residues generates a mutant Bm-P143 protein that is capable of triggering rRNA degradation in BM-N cells. These results indicate that BmNPV evolved a unique P143 protein to evade the antiviral response and allow replication in B. mori cells.
我们之前证明，感染苜蓿银纹夜蛾多角体病毒（AcMNPV）后，家蚕BM - N细胞中的核糖体RNA（rRNA）会发生快速且广泛的降解，这是由AcMNPV P143（Ac - P143）蛋白触发的。在此，我们表明Ac - P143蛋白位于514至599位之间的六个氨基酸残基参与了BM - N细胞中的rRNA降解。这六个残基在来自AcMNPV、HycuMNPV、SeMNPV和SpltMNPV的P143蛋白中高度保守，这些病毒感染后会在BM - N细胞中触发rRNA降解，但在Bm - P143蛋白中仅部分保守，Bm - P143蛋白不会在BM - N细胞中诱导rRNA降解。我们还证明，仅将Bm - P143蛋白的两个选定残基（N565S/L578F）替换为相应的Ac - P143蛋白残基，就会产生一种能够在BM - N细胞中触发rRNA降解的突变型Bm - P143蛋白。这些结果表明，家蚕核型多角体病毒（BmNPV）进化出了一种独特的P143蛋白来逃避抗病毒反应并允许在家蚕细胞中复制。
