Kabza Adam M, Sczepanski Jonathan T
Department of Chemistry, Texas A&M University, College Station, TX, 77843, USA.
Chembiochem. 2017 Sep 19;18(18):1824-1827. doi: 10.1002/cbic.201700362. Epub 2017 Aug 10.
To facilitate isolation of l-aptamers with novel RNA-binding properties, we employed a cationic nucleotide, 5-aminoallyluridine, during the mirror image in vitro selection process. Through this effort, we identified a modified l-RNA aptamer (MlRA) capable of binding oncogenic precursor microRNA 19a (pre-miR-19a) with exceptional affinity, and we showed that cationic modification is absolutely critical for binding. Furthermore, formation of the MlRA-pre-miR-19a complex inhibited Dicer-mediated cleavage of the pre-miR, thus blocking formation of the mature functional microRNA. The MlRA reported here not only represents the first l-aptamer to be evolved by using modified nucleotides but also the first modified aptamer (of any type) to be selected against a structured RNA target. Our results demonstrate that functionalized l-aptamers, which are intrinsically nuclease-resistant, provide an attractive approach for developing robust RNA-binding reagents.
为便于分离具有新型RNA结合特性的L-适体，我们在镜像体外筛选过程中使用了一种阳离子核苷酸5-氨基烯丙基尿苷。通过这项工作，我们鉴定出一种能够以非凡亲和力结合致癌前体微小RNA 19a（pre-miR-19a）的修饰L-RNA适体（MlRA），并且我们表明阳离子修饰对于结合至关重要。此外，MlRA-pre-miR-19a复合物的形成抑制了Dicer介导的pre-miR切割，从而阻断了成熟功能性微小RNA的形成。本文报道的MlRA不仅代表了首个通过使用修饰核苷酸进化而来的L-适体，也是首个针对结构化RNA靶标筛选出的修饰适体（任何类型）。我们的结果表明，本质上抗核酸酶的功能化L-适体为开发强大的RNA结合试剂提供了一种有吸引力的方法。
