Abstract：
OLE (ornate, large, extremophilic) RNAs are members of a noncoding RNA class present in many Gram-positive, extremophilic bacteria. The large size, complex structure, and extensive sequence conservation of OLE RNAs are characteristics consistent with the hypothesis that they likely function as ribozymes. The OLE RNA representative from Halalkalibacterium halodurans is known to localize to the phospholipid membrane and requires at least three essential protein partners: OapA, OapB, and OapC. However, the precise biochemical functions of this unusual ribonucleoprotein (RNP) complex remain unknown. Genetic disruption of OLE RNA or its partners revealed that the complex is beneficial under diverse stress conditions. To search for additional links between OLE RNA and other cellular components, we used phylogenetic profiling to identify proteins that are either correlated or anticorrelated with the presence of OLE RNA in various bacterial species. This analysis revealed strong correlations between the essential protein-binding partners of OLE RNA and organisms that carry the ole gene. Similarly, proteins involved in sporulation are correlated, suggesting a potential role for the OLE RNP complex in spore formation. Intriguingly, the Mg2+ transporter MpfA is strongly anticorrelated with OLE RNA. Evidence indicates that MpfA is structurally related to OapA and therefore MpfA may serve as a functional replacement for some contributions otherwise performed by the OLE RNP complex in species that lack this device. Indeed, OLE RNAs might represent an ancient RNA class that enabled primitive organisms to sense and respond to major cellular stresses.IMPORTANCEOLE (ornate, large, extremophilic) RNAs were first reported nearly 20 years ago, and they represent one of the largest and most intricately folded noncoding RNA classes whose biochemical function remains to be established. Other RNAs with similar size, structural complexity, and extent of sequence conservation have proven to catalyze chemical transformations. Therefore, we speculate that OLE RNAs likewise operate as ribozymes and that they might catalyze a fundamental reaction that has persisted since the RNA World era-a time before the emergence of proteins in evolution. To seek additional clues regarding the function of OLE RNA, we undertook a computational effort to identify potential protein components of the OLE ribonucleoprotein (RNP) complex or other proteins that have functional links to this device. This analysis revealed known protein partners and several additional proteins that might be physically or functionally linked to the OLE RNP complex. Finally, we identified a Mg2+ transporter protein, MpfA, that strongly anticorrelates with the OLE RNP complex. This latter result suggests that MpfA might perform at least some functions that are like those carried out by the OLE RNP complex.
摘要：
OLE（华丽，大,极端)RNA是存在于许多革兰氏阳性中的非编码RNA类别的成员，嗜极端细菌。大尺寸，复杂结构,OLERNA的广泛序列保守性是与它们可能作为核酶起作用的假设一致的特征。已知来自Halalkalalibaciumhalodurans的OLERNA代表定位于磷脂膜，并且需要至少三个必需的蛋白质伴侣：OapA，OapB,OapC然而,这种不寻常的核糖核蛋白（RNP）复合物的精确生化功能仍然未知。OLERNA或其伴侣的遗传破坏表明，该复合物在多种胁迫条件下是有益的。为了搜索OLERNA和其他细胞成分之间的其他联系，我们使用系统发育谱分析来鉴定与各种细菌中OLERNA的存在相关或反相关的蛋白质.该分析揭示了OLERNA的必需蛋白结合伴侣与携带ole基因的生物体之间的强相关性。同样，参与孢子形成的蛋白质是相关的，提示OLERNP复合物在孢子形成中的潜在作用。有趣的是，Mg2+转运体MpfA与OLERNA强烈反相关。证据表明，MpfA与OapA在结构上相关，因此MpfA可以作为OLERNP复合物在缺乏该装置的物种中的某些贡献的功能替代品。的确,OLERNA可能代表一种古老的RNA类别，使原始生物体能够感知并响应主要的细胞压力。IMPORTANCEOLE(华丽，大,极端)RNA在近20年前首次被报道，它们代表了最大和最复杂折叠的非编码RNA类别之一，其生化功能仍有待建立。其他大小相似的RNA，结构复杂性，和序列守恒的程度已被证明可以催化化学转化。因此,我们推测，OLERNA同样作为核酶起作用，并且它们可能催化自RNA世界时代以来一直存在的基本反应-在进化中蛋白质出现之前的时间。为了寻找有关OLERNA功能的其他线索，我们进行了一项计算工作，以鉴定OLE核糖核蛋白（RNP）复合物的潜在蛋白质成分或与该设备具有功能链接的其他蛋白质。该分析揭示了已知的蛋白质配偶体和可能与OLERNP复合物物理或功能连接的几种其他蛋白质。最后,我们鉴定了一种Mg2+转运蛋白，MpfA,与OLERNP复合物强烈反相关。后一个结果表明MpfA可能执行至少一些类似于OLERNP复合物执行的功能。
