Pseudouridine Modification Inhibits Muscleblind-like 1 (MBNL1) Binding to CCUG Repeats and Minimally Structured RNA through Reduced RNA Flexibility
Pseudouridine Modification Inhibits Muscleblind-like 1 (MBNL1) Binding to CCUG Repeats and Minimally Structured RNA through Reduced RNA Flexibility
复制标题
DOI：
10.1074/jbc.m116.770768
复制
发表时间：
2017-03-01
影响因子：
4.8
通讯作者：
Berglund, J. Andrew
中科院分区：
文献类型：
--
作者：
delorimier, Elaine;Hinman, Melissa N.;Berglund, J. Andrew
强直性肌营养不良2型是一种遗传性神经肌肉疾病，其主要原因是在bar CHC型锌指(N)和bar-(B)在bar-(P)和bar-rotein(CNBP)基因的bar结合(P)下，(C)非编码区扩增的CCUG重复序列表达。这些CCUG重复序列结合和隔离一族RNA结合蛋白，称为类蝇子样1、2和3(MBNL1、MBNL2和MBNL3)，隔离在致病性中发挥重要作用。MBNL蛋白是与共同的RNA序列YGCY(Y=嘧啶)结合的选择性剪接调节因子。这种共有的序列在有毒的RNA(CCUG重复)和细胞RNA底物中发现，MBNL蛋白已被证明与其结合。用假尿苷(Psi)取代CCUG重复序列中的尿苷，导致MBNL1结合略有减少。有趣的是，对含有YGCY基序的最低结构RNA的Psi修饰导致了对MBNL1结合的更强的抑制。CCUG重复和最低结构RNA结合之间不同程度的抑制似乎是由于能够修饰YGCY基序中的两个嘧啶，而这在CCUG重复中是不可能的。对未经修饰和假尿苷酸化的最低结构RNA的分子动力学研究表明，降低最低结构RNA的灵活性会导致MBNL1结合的减少。
Myotonic dystrophy type 2 is a genetic neuromuscular disease caused by the expression of expanded CCUG repeat RNAs from the non-coding region of the (C) under bar CHC-type zinc finger (n) under bar ucleic acid- (b) under bar inding (p) under bar rotein (CNBP) gene. These CCUG repeats bind and sequester a family of RNA-binding proteins known as Muscleblind-like 1, 2, and 3 (MBNL1, MBNL2, and MBNL3), and sequestration plays a significant role in pathogenicity. MBNL proteins are alternative splicing regulators that bind to the consensus RNA sequence YGCY (Y = pyrimidine). This consensus sequence is found in the toxic RNAs (CCUG repeats) and in cellular RNA substrates that MBNL proteins have been shown to bind. Replacing the uridine in CCUG repeats with pseudouridine (Psi) resulted in a modest reduction of MBNL1 binding. Interestingly, Psi modification of a minimally structured RNA containing YGCY motifs resulted in more robust inhibition of MBNL1 binding. The different levels of inhibition between CCUG repeat and minimally structured RNA binding appear to be due to the ability to modify both pyrimidines in the YGCY motif, which is not possible in the CCUG repeats. Molecular dynamic studies of unmodified and pseudouridylated minimally structured RNAs suggest that reducing the flexibility of the minimally structured RNA leads to reduced binding by MBNL1.