Branlant C, Krol A, Ebel J P, Lazar E, Haendler B, Jacob M
EMBO J. 1982;1(10):1259-65. doi: 10.1002/j.1460-2075.1982.tb00022.x.
We previously reported common structural features within the 3'-terminal regions of U1, U4, and U5 RNAs. To check whether these features also exist in U2 RNA, the primary and secondary structures of the 3'-terminal regions of chicken, pheasant, and rat U2 RNAs were examined. Whereas no difference was observed between pheasant and chicken, the chicken and rat sequences were only 82.5% homologous. Such divergence allowed us to propose a unique model of secondary structure based on maximum base-pairing and secondary structure conservation. The same model was obtained from the results of limited digestion of U2 RNA with various nucleases. Comparison of this structure with those of U1, U4, and U5 RNAs shows that the four RNAs share a common structure designated as domain A, and consisting of a free single-stranded region with the sequence Pu-A-(U)n-G-Pup flanked by two hairpins. The hairpin on the 3' side is very stable and has the sequence Py-N-Py-Gp in the loop. The presence of this common domain is discussed in connection with relationships among U RNAs and common protein binding sites.
我们之前报道了U1、U4和U5 RNA 3'-末端区域内的共同结构特征。为了检查这些特征是否也存在于U2 RNA中，我们研究了鸡、雉和大鼠U2 RNA 3'-末端区域的一级和二级结构。虽然雉和鸡之间未观察到差异，但鸡和大鼠的序列同源性仅为82.5%。这种差异使我们能够基于最大碱基配对和二级结构保守性提出一个独特的二级结构模型。用各种核酸酶对U2 RNA进行有限消化的结果也得到了相同的模型。将该结构与U1、U4和U5 RNA的结构进行比较，结果表明这四种RNA共享一个称为结构域A的共同结构，该结构由一个游离单链区域组成，其序列为Pu-A-(U)n-G-Pup，两侧是两个发夹结构。3'侧的发夹结构非常稳定，其环区序列为Py-N-Py-Gp。结合U RNA之间的关系和常见蛋白质结合位点，讨论了这个共同结构域的存在。
