MRNA molecules containing murine leukemia virus packaging signals are encapsidated as dimers
MRNA molecules containing murine leukemia virus packaging signals are encapsidated as dimers
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DOI：
10.1128/jvi.78.20.10927-10938.2004
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发表时间：
2004-10-01
影响因子：
5.4
通讯作者：
Rein, A
中科院分区：
文献类型：
--
作者：
Hibbert, CS;Mirro, J;Rein, A
其他人的先前工作已经表明，psi的插入（即，将来自莫洛尼鼠白血病病毒（MLV）基因组的RNA（前导序列）插入非病毒mRNA的3'非翻译区，导致该RNA在MLV颗粒中的特异性折叠。我们现在报告说，这些RNA，像基因组RNA一样，以二聚体的形式被糖苷化。这些二聚体具有与MLV基因组RNA二聚体相同的热稳定性;与它们一样，如果从成熟病毒体中分离，这些二聚体比从未成熟病毒体中分离更稳定。我们的特点是，mRNAs的mRNAs中含有MLV psi的缺失或截短，或与MLV相关的急性转化病毒的psi序列。结果表明，基因组RNA中的二聚体连接可以完全归因于基因组的psi区域。虽然这一结论与早期对成熟MLV二聚体的电子显微镜研究一致，但它是关于任何逆转录病毒未成熟二聚体中连接位点的第一个证据。由于Psi（+）mRNA不像基因组RNA那样被糖苷化，因此它仅存在于少数病毒体中。然而，它是二聚体的事实有力地证明了这些分子中的两个被包装成颗粒。我们还发现，接吻环是不必要的，这种凝聚或成熟的二聚体的稳定性，但作出了重大贡献的不成熟的二聚体的稳定性。我们的研究结果是一致的假设，包装信号涉及一个二聚体结构，其中的RNA加入GACG环之间的分子间相互作用。
Prior work by others has shown that insertion of psi (i.e., leader) sequences from the Moloney murine leukemia virus (MLV) genome into the 3' untranslated region of a nonviral mRNA leads to the specific encapsidation of this RNA in MLV particles. We now report that these RNAs are, like genomic RNAs, encapsidated as dimers. These dimers have the same thermostability as MLV genomic RNA dimers; like them, these dimers are more stable if isolated from mature virions than from immature virions. We characterized encapsidated mRNAs containing deletions or truncations of MLV psi or with psi sequences from MLV-related acute transforming viruses. The results indicate that the dimeric linkage in genomic RNA can be completely attributed to the psi region of the genome. While this conclusion agrees with earlier electron microscopic studies on mature MLV dimers, it is the first evidence as to the site of the linkage in immature dimers for any retrovirus. Since the Psi(+) mRNA is not encapsidated as well as genomic RNA, it is only present in a minority of virions. The fact that it is nevertheless dimeric argues strongly that two of these molecules are packaged into particles together. We also found that the kissing loop is unnecessary for this coencapsidation or for the stability of mature dimers but makes a major contribution to the stability of immature dimers. Our results are consistent with the hypothesis that the packaging signal involves a dimeric structure in which the RNAs are joined by intermolecular interactions between GACG loops.