Rapid evolution of mammalian X-linked testis microRNAs
Rapid evolution of mammalian X-linked testis microRNAs
复制标题
哺乳动物X连锁睾丸microRNA的快速进化
DOI：
10.1186/1471-2164-10-97
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发表时间：
2009-03-04
期刊：
影响因子：
4.4
通讯作者：
Sha, Jiahao
中科院分区：
文献类型：
--
作者：
Guo, Xuejiang;Su, Bing;Sha, Jiahao
背景微RNA（microRNAs，miRNAs）是一类长度约为21个核苷酸的非编码小RNA，已成为分子生物学研究的热点。哺乳动物的miRNAs被认为调节了大约30%的蛋白质编码基因。以前的研究都集中在高度保守的miRNA，但非保守的miRNA代表了一个潜在的重要来源的新功能在evolution.ResultsAn分析的染色体分布的miRNA的X染色体上的密度较高的miRNA相比，在所有8种哺乳动物的常染色体上的平均密度进行了分析。然而，这种分布模式并不适用于哺乳动物以外的物种。此外，通过比较人和小鼠的miRNA，我们发现X-连锁的miRNA比常染色体的miRNA具有更高的替换率。由于在小鼠睾丸中发现了最高比例的X-连锁miRNA，我们测试了睾丸miRNA在X染色体上比在常染色体上进化得更快的假设。成熟的X连锁睾丸miRNA在小鼠和人类之间的平均替换率几乎是常染色体上成熟睾丸miRNA的25倍。与此相反，成熟的miRNAs的前体不表达在睾丸中，没有显着差异的替代率之间的X染色体和常染色体被发现。在哺乳动物中，X-连锁睾丸miRNAs的快速进化，也观察到在啮齿动物和灵长类动物。
BackgroundMicroRNAs (miRNAs), which are small, non-coding RNAs approximately 21-nucleotides in length, have become a major focus of research in molecular biology. Mammalian miRNAs are proposed to regulate approximately 30% of all protein-coding genes. Previous studies have focused on highly conserved miRNAs, but nonconserved miRNAs represent a potentially important source of novel functionalities during evolution.ResultsAn analysis of the chromosome distribution of miRNAs showed higher densities of miRNAs on the X chromosome compared to the average densities on autosomes in all eight mammalian species analyzed. The distribution pattern did not, however, apply well to species beyond mammals. In addition, by comparing orthologous human and mouse miRNAs, we found that X-linked miRNAs had higher substitution rates than autosomal miRNAs. Since the highest proportion of X-linked miRNAs were found in mouse testis, we tested the hypothesis that testis miRNAs are evolving faster on the X chromosome than on autosomes. Mature X-linked testis miRNAs had an average substitution rate between mouse and human that was almost 25-fold higher than mature testis miRNAs on autosomes. In contrast, for mature miRNAs with precursors not expressed in testis, no significant difference in the substitution rate between the X chromosome and autosomes was found. Among mammals, the rapid evolution of X-linked testis miRNAs was also observed in rodents and primates.ConclusionThe rapid evolution of X-linked testis miRNAs implies possible important male reproductive functions and may contribute to speciation in mammals.