Hahn H, Palmenberg A C
Institute for Molecular Virology, University of Wisconsin, Madison 53706, USA.
J Virol. 1996 Oct;70(10):6870-5. doi: 10.1128/JVI.70.10.6870-6875.1996.
Sixteen substitution mutations of the conserved DvExNPGP sequence, implicated in cardiovirus and aphthovirus primary polyprotein cleavage, were created in encephalomyocarditis virus cDNA, expressed, and characterized for processing activity. Nearly all the mutations severely decreased the efficiency of the primary cleavage reaction during cell-free synthesis of viral precursors, indicating a stringent requirement for the natural sequence in this processing event. When representative mutations were tested in full-length genomic contexts, they were lethal and no revertants were observed. Not only were the primary cleavage reactions deficient in these polyproteins, but subsequent cleavage of P1 by endogenous or exogenous 3C pro was also impaired. This indicates that primary cleavage has a role in the proper processing of the viral capsid precursor.
在脑心肌炎病毒cDNA中产生了16个保守的DvExNPGP序列的替代突变，这些突变与心病毒和口疮病毒主要多聚蛋白的切割有关，对其进行了表达并对加工活性进行了表征。几乎所有突变都严重降低了病毒前体无细胞合成过程中初级切割反应的效率，表明该加工过程对天然序列有严格要求。当在全长基因组背景下测试代表性突变时，它们是致死性的，未观察到回复突变体。这些多聚蛋白不仅初级切割反应存在缺陷，而且P1被内源性或外源性3C蛋白酶的后续切割也受到损害。这表明初级切割在病毒衣壳前体的正确加工中起作用。
