A Conserved Domain in the Coronavirus Membrane Protein Tail Is Important for Virus Assembly
A Conserved Domain in the Coronavirus Membrane Protein Tail Is Important for Virus Assembly
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DOI：
10.1128/jvi.01131-10
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发表时间：
2010-11-01
影响因子：
5.4
通讯作者：
Hogue, Brenda G.
中科院分区：
文献类型：
--
作者：
Arndt, Ariel L.;Larson, Blake J.;Hogue, Brenda G.
冠状病毒膜（M）蛋白通过M-M、M-刺突（S）和M-核衣壳（N）蛋白相互作用在病毒组装中起关键作用。M羧基末端胞内结构域包含第三个跨膜（TM）结构域之后的保守结构域（CD）。CD（SWWSFNPETNNL）在小鼠肝炎病毒中的重要性进行了研究与一组突变蛋白，使用遗传分析和瞬时表达试验。不容许带负电荷的E-121的电荷反转。仅在一次传代后，回收的病毒中的赖氨酸（K）和精氨酸（R）取代分别被中性电荷的谷氨酰胺（Q）和亮氨酸（L）取代。E（121）Q和E121 LM蛋白与E共表达时能够形成病毒样颗粒（VLP），而E121 R和E121 K蛋白则不能。前四个或最后四个残基的丙氨酸取代导致病毒具有显著受损的表型和蛋白质，这些蛋白质不能组装VLP或被拯救到包膜中。所有回收的用丙氨酸取代SWWS残基的病毒在M的第一个TM中都有第二个位点的部分补偿变化。丙氨酸取代脯氨酸对病毒的影响很小。N蛋白与一些M突变体共表达增加了VLP的产生。结果总体上表明，CD通过帮助介导基本的M-M相互作用对病毒包膜的形成是重要的，并且N蛋白的存在可能有助于在病毒组装期间稳定M复合物。
Coronavirus membrane (M) proteins play key roles in virus assembly, through M-M, M-spike (S), and M-nucleocapsid (N) protein interactions. The M carboxy-terminal endodomain contains a conserved domain (CD) following the third transmembrane (TM) domain. The importance of the CD (SWWSFNPETNNL) in mouse hepatitis virus was investigated with a panel of mutant proteins, using genetic analysis and transient-expression assays. A charge reversal for negatively charged E-121 was not tolerated. Lysine (K) and arginine (R) substitutions were replaced in recovered viruses by neutrally charged glutamine (Q) and leucine (L), respectively, after only one passage. E(121)Q and E121L M proteins were capable of forming virus-like particles (VLPs) when coexpressed with E, whereas E121R and E121K proteins were not. Alanine substitutions for the first four or the last four residues resulted in viruses with significantly crippled phenotypes and proteins that failed to assemble VLPs or to be rescued into the envelope. All recovered viruses with alanine substitutions in place of SWWS residues had second-site, partially compensating, changes in the first TM of M. Alanine substitution for proline had little impact on the virus. N protein coexpression with some M mutants increased VLP production. The results overall suggest that the CD is important for formation of the viral envelope by helping mediate fundamental M-M interactions and that the presence of the N protein may help stabilize M complexes during virus assembly.