School of Chemistry, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK.
Nucleic Acids Res. 2013 Aug;41(14):7153-66. doi: 10.1093/nar/gkt470. Epub 2013 Jun 6.
The CUG-BP, Elav-like family (CELF) of RNA-binding proteins control gene expression at a number of different levels by regulating pre-mRNA splicing, deadenylation and mRNA stability. We present structural insights into the binding selectivity of CELF member 1 (CELF1) for GU-rich mRNA target sequences of the general form 5'-UGUNxUGUNyUGU and identify a high affinity interaction (Kd ∼ 100 nM for x = 2 and y = 4) with simultaneous binding of all three RNA recognition motifs within a single 15-nt binding element. RNA substrates spin-labelled at either the 3' or 5' terminus result in differential nuclear magnetic resonance paramagnetic relaxation enhancement effects, which are consistent with a non-sequential 2-1-3 arrangement of the three RNA recognition motifs on UGU sites in a 5' to 3' orientation along the RNA target. We further demonstrate that CELF1 binds to dispersed single-stranded UGU sites at the base of an RNA hairpin providing a structural rationale for recognition of CUG expansion repeats and splice site junctions in the regulation of alternative splicing.
CUG-BP、Elav 样家族（CELF）的 RNA 结合蛋白通过调节前体 mRNA 剪接、脱腺苷酸化和 mRNA 稳定性，在多个不同水平上控制基因表达。我们提出了 CELF 成员 1（CELF1）对具有一般形式 5'-UGUNxUGUNyUGU 的 GU 富集 mRNA 靶序列的结合选择性的结构见解，并确定了与单个 15-nt 结合元件内的所有三个 RNA 识别基序的同时结合的高亲和力相互作用（Kd∼100 nM，x=2 和 y=4）。在 3'或 5'末端进行自旋标记的 RNA 底物会导致核磁共振顺磁弛豫增强效应的差异，这与三个 RNA 识别基序在 UGU 位点上沿 RNA 靶标从 5'到 3'方向的非连续 2-1-3 排列一致。我们进一步证明，CELF1 结合到 RNA 发夹底部的离散单链 UGU 位点，为识别 CUG 扩展重复和剪接位点连接在调节选择性剪接中的作用提供了结构基础。
