NMR structure determination of a nucleoprotein complex between the human protein muscleblind and myotonic dystrophy associated double stranded RNA

强直性肌营养不良(DM)是由CUG或CCUG在某些前mRNAs的非翻译区广泛扩张引起的。这些扩张形成稳定的双链RNA发夹结构和隔离人类肌肉盲蛋白(MBNL)，调节各种重要的前mRNAs的选择性剪接。MBNL从其作用部位耗尽导致肌强直、心脏传导阻滞和白内障，这些都是糖尿病发病机制的共同特征。MBNL含有两对CysCysCysHis锌指基序，负责RNA结合。该项目的目标是通过异核核磁共振波谱确定与DM相关的双链RNA形成的复合体中MBNL锌指的三维结构。由于MBNL与双链RNA相互作用，并且与同源单链RNA结合锌指蛋白相比，显示出改变的序列特异性，因此深入了解这些结合方面根本差异的结构决定因素是本研究的另一个目的。

Myotonic dystrophy (DM) is caused by extensive CUG or CCUG expansions in untranslated regions of certain pre-mRNAs. These expansions form stable double stranded RNA hairpin structures and sequester human muscleblind proteins (MBNL), which regulate alternative splicing of various important pre-mRNAs. The depletion of MBNL from its site of action leads to myotonia, heart blocks, and cataracts that are common features in DM pathogenesis. MBNL contains two pairs of CysCysCysHis zinc finger motifs, which are responsible for RNA binding. The goal of the proposed project is the determination of the three dimensional structure of the MBNL zinc fingers in complex with DM associated double stranded RNA by heteronuclear nuclear magnetic resonance (NMR) spectroscopy. Since MBNL interacts with double stranded RNA and exhibits altered sequence specificity in comparison to homologous single stranded RNA binding zinc finger proteins gaining insights into the structural determinants of these fundamental differences in binding are additional aims of this study.