PLUS AND MINUS RNAS OF PEACH LATENT MOSAIC VIROID SELF-CLEAVE INVITRO VIA HAMMERHEAD STRUCTURES
PLUS AND MINUS RNAS OF PEACH LATENT MOSAIC VIROID SELF-CLEAVE INVITRO VIA HAMMERHEAD STRUCTURES
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DOI：
10.1073/pnas.89.9.3711
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发表时间：
1992-05-01
影响因子：
11.1
通讯作者：
FLORES, R
中科院分区：
文献类型：
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作者：
HERNANDEZ, C;FLORES, R
桃潜伏花叶类病毒（Peach latent mosaic vioid，PLMVd）是桃潜伏花叶病的病原体，经序列测定，它是一个337个核苷酸的环状RNA分子，以最低自由能模式折叠时呈分枝状构象。PLMVd与其他类病毒和一些卫星RNA具有有限的同源性，但它不具有任何典型类病毒亚群的中心保守序列特征。然而，PLMVd序列的大约三分之一的片段具有在两种极性的RNA中形成锤头结构所需的元件，所述锤头结构被提议在鳄梨晒斑类病毒（ASBVd）和一些卫星RNA的体外自切割中起作用。加上和减去部分和全长的RNA转录本PLMVd含有锤头结构显示自切割在转录过程中和纯化后，这些结构的预测。这些数据与PLMVd锤头结构的高稳定性一致，与ASBVd的那些相比，PLMVd锤头结构更类似于一些卫星RNA的相应结构，并且表明PLMVd的自切割反应最可能由单个锤头结构介导。我们的研究结果支持列入PLMVd在类病毒亚组ASBVd，其成员的特点是他们的能力，自我切割在体外，并可能在体内，通过锤头状结构为代表。一个一致的系统发育树表明，PLMVd，连同ASBVd，可能代表类病毒和类病毒样卫星RNA之间的进化联系。
Peach latent mosaic viroid (PLMVd), the causal agent of peach latent mosaic disease, has been sequenced and found to be a circular RNA molecule of 337 nucleotide residues, which adopts a branched conformation when it is folded in the model of lowest free energy. PLMVd exhibits limited homologies with other viroids and some satellite RNAs, but it does not have any of the central conserved sequences characteristic of the subgroups of typical viroids. However, a segment of approximately one-third of the PLMVd sequence has the elements required to form in the RNAs of both polarities the hammerhead structures proposed to act in the in vitro self-cleavage of avocado sunblotch viroid (ASBVd) and some satellite RNAs. Plus and minus partial- and full-length RNA transcripts of PLMVd containing the hammerhead structures displayed self-cleavage during transcription and after purification as predicted by these structures. These data are consistent with the high stability of the PLMVd hammerhead structures, more similar to the corresponding structures of some satellite RNAs than to those of ASBVd, and indicate that the self-cleavage reactions of PLMVd are most probably mediated by single hammerhead structures. Our results support the inclusion of PLMVd in a viroid subgroup represented by ASBVd, whose members are characterized by their ability to self-cleave in vitro, and probably in vivo, through hammerhead structures. A consensus phylogenetic tree has been obtained suggesting that PLMVd, together with ASBVd, may represent an evolutionary link between viroids and viroid-like satellite RNAs.