Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri 63110, USA.
RNA. 2014 Jul;20(7):1035-45. doi: 10.1261/rna.044255.114. Epub 2014 May 19.
In the vertebrate lineage of the U1A/U2B″/SNF protein family, the U1A and U2B″ proteins bind to RNA stem-loops in the U1 or U2 snRNPs, respectively. However, their specialization is fairly recent, as they evolved from a single ancestral protein. The progress of their specialization (subfunctionalization) can be monitored by the amino acid sequence changes that give rise to their modern RNA-binding specificity. Using ancestral sequence reconstruction to predict the intermediates on the evolutionary branch, a probable path of sequential changes is defined for U1A and U2B″. The RNA-binding affinity for U1A/U2B″ protein ancestors was measured using modern U1 and U2 snRNA stem-loops and RNA stem-loop variants to understand how the proteins' RNA specificities evolved.
在脊椎动物 U1A/U2B″/SNF 蛋白家族的谱系中，U1A 和 U2B″ 蛋白分别与 U1 或 U2 snRNP 中的 RNA 茎环结合。然而，它们的专业化是相当新的，因为它们是从单个祖先蛋白进化而来的。它们的专业化（亚功能化）的进展可以通过导致其现代 RNA 结合特异性的氨基酸序列变化来监测。使用祖先序列重建来预测进化分支上的中间体，为 U1A 和 U2B″ 定义了一个可能的顺序变化路径。使用现代 U1 和 U2 snRNA 茎环和 RNA 茎环变体来测量 U1A/U2B″ 蛋白祖先的 RNA 结合亲和力，以了解蛋白质的 RNA 特异性是如何进化的。
