Riley Donald E, Jeon Joon Seong, Krieger John N
Department of Urology, University of Washington, Seattle, WA 98195, USA.
Biochem Biophys Res Commun. 2007 Apr 13;355(3):619-25. doi: 10.1016/j.bbrc.2007.01.200. Epub 2007 Feb 15.
We previously demonstrated that many "weak-folding" simple repeats were replaced during evolution by alternative weak-folding repeats. This suggested repeat selection at the level of higher order structure potential. Here, we demonstrate similar phenomena for "strong-folding" simple repeats in non-coding DNA. The Rabgap1 gene's 3' UTR contained the self-complementary repeat (AT)n in Homo sapiens but, in Mus musculus, this site was occupied by the complementary repeats (GT)n and (AC)n. Similarly, primate Plag1 UTRs contained various (GT)n-(AC)n palindromes but in rodents, this site was occupied by (AT)n, preserving folding potential more than primary sequence. The Znf516, Senp1, Rock2, and other UTRs exhibited similar replacements. In the Bnc2 UTR, (AT)n was replaced by sequences that evolved with approximate symmetry about a central axis, a pattern difficult to explain without invoking selection to preserve secondary structure. These observations reflect a predictable evolutionary pattern for some common non-coding genomic sequences.
我们之前证明，在进化过程中，许多“弱折叠”简单重复序列被其他弱折叠重复序列所取代。这表明在高阶结构潜力水平上存在重复序列选择。在此，我们证明非编码DNA中的“强折叠”简单重复序列也存在类似现象。人类Rabgap1基因的3' UTR含有自我互补重复序列(AT)n，但在小家鼠中，该位点被互补重复序列(GT)n和(AC)n占据。同样，灵长类动物Plag1的UTR含有各种(GT)n-(AC)n回文序列，但在啮齿动物中，该位点被(AT)n占据，相比于一级序列，其更多地保留了折叠潜力。Znf516、Senp1、Rock2和其他UTR也表现出类似的取代情况。在Bnc2的UTR中，(AT)n被围绕中心轴具有近似对称性进化的序列所取代，这种模式如果不考虑为保留二级结构而进行的选择则很难解释。这些观察结果反映了一些常见非编码基因组序列可预测的进化模式。
