Evolutionary history of 4.5SH RNA
Evolutionary history of 4.5SH RNA
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DOI：
10.1093/molbev/msi140
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发表时间：
2005-07-01
影响因子：
10.7
通讯作者：
Kramerov, DA
中科院分区：
文献类型：
--
作者：
Gogolevskaya, IK;Koval, AP;Kramerov, DA
4.5SH RNA是一种94-nt的小RNA，功能未知。已知这种RNA存在于小鼠、大鼠和仓鼠细胞中;然而，在人类、兔子和鸡中没有发现。在小鼠基因组中，4.5SH RNA基因是长（4.2 kb）串联重复（类似于800个拷贝）单元的一部分。在这里，我们发现，4.5SH RNA基因只存在于六个家庭的啮齿动物，包括Myodonta分支：鼠科，仓鼠科。对来自这些科的啮齿类动物的互补DNA的分析表明，4.5SH RNA分子具有普遍的进化保守性和一定的种内异质性。重复序列中包括挪威大鼠、鼹鼠、仓鼠和跳鼠基因组中的4.5SH RNA基因。在跳鼠基因组中，这些重复序列长4.0 kb，串联排列，类似于小鼠和大鼠基因组DNA中的相应排列。对大鼠和跳鼠4.5SH RNA基因重复序列的测序表明，基因侧翼序列的进化速度很快，除了4.5SH RNA基因本身外，远缘啮齿动物（小鼠和大鼠与跳鼠）的重复序列没有明显的相似性。4.5SH RNA基因核苷酸序列的保守性表明该RNA可能处于选举压力下，因此可能具有功能。来自不同啮齿动物的重复序列具有相似的长度，并且包含许多简单的短重复序列。结果表明，长的插入、缺失和简单的序列扩增在4.5SH RNA重复序列的进化中起着重要作用。4.5 SH RNA基因可能起源于50-85 MYA的Myodonta祖先中的一个B I短散布元件的拷贝。进一步的进化导致了每个谱系中重复序列的巨大变化，仅保留了4.5SH RNA基因。该基因和其他一些起源较晚的基因一样，可能是研究非蛋白质编码基因的产生和进化的有用模型。
4.5SH RNA is a 94-nt small RNA with unknown function. This RNA is known to be present in the mouse, rat, and hamster cells; however, it is not found in human, rabbit, and chicken. In the mouse genome, the 4.5SH RNA gene is a part of a long (4.2 kb) tandem repeat (similar to 800 copies) unit. Here, we found that 4.5SH RNA genes are present only in rodents of six families that comprise the Myodonta clade: Muridae, Cricetidae. Spalacidae, Rhizomyidae, Zapodidae, and Dipodidae, The analysis of complementary DNA derived from the rodents of these families showed general evolutionary conservation of 4.5SH RNA and some intraspecific heterogeneity of these RNA molecules. 4.5SH RNA genes in the Norway rat, mole rat, hamster and jerboa genomes are included in the repeated sequences. In the jerboa genome these repeats are 4.0-kb long and arranged tandemly, similar to the corresponding arrangements in the mouse and rat genomic DNA. Sequencing of the rat and jerboa DNA repeats containing 4.5SH RNA genes showed fast evolution of the gene-flanking sequences, The repeat sequences of the distantly related rodents (mouse and rat vs. jerboa) have no apparent similarity except for the 4.5SH RNA gene itself. Conservation of the 4.5SH RNA gene nucleotide sequence indicates that this RNA is likely to be under election pressure and, thus, may have a function. The repeats from the different rodents have similar lengths and contain many simple short repeats. The data obtained suggest that long insertions, deletions, and simple sequence amplifications significantly contribute in the evolution of the repeats containing 4.5SH RNA genes'. The 4.5SH RNA gene seems to have originated 50-85 MYA in a Myodonta ancestor from a copy of the B I short interspersed element, The amplification of the gene with the flanking sequences could result from the supposed cellular requirement of the intensive synthesis of 4.5SH RNA. Further Myodonta evolution led to dramatic changes of the repeat sequences in every lineage with the conservation of the 4.5SH RNA genes only. This gene, like some other relatively recently originated genes, could be a useful model for studying generation and evolution of non-protein-coding genes.