Autoregulation of MBNL1 function by exon 1 exclusion from MBNL1 transcript.
Autoregulation of MBNL1 function by exon 1 exclusion from MBNL1 transcript.
复制标题
DOI：
10.1093/nar/gkw1158
复制
发表时间：
2017-02-28
影响因子：
14.9
通讯作者：
Sobczak K
中科院分区：
文献类型：
--
作者：
Konieczny P;Stepniak-Konieczna E;Taylor K;Sznajder LJ;Sobczak K
肌盲样蛋白（MBNL）是RNA代谢的调节因子。在组织分化过程中，MBNL的水平增加，而它们的功能不足在强直性肌营养不良（DM）中起着至关重要的作用。与免疫沉淀蛋白颗粒交联的RNA分子的深度测序（CLIP-seq）显示，MBNL 1结合MBNL 1外显子1（e1），其编码MBNL 1蛋白的5 ′ UTR的主要部分和氨基末端区域。我们测试了几个假设MBNL 1结合到自己的转录可能的自动调节功能。我们的数据表明，MBNLs诱导跳过e1从前体MBNL 1 mRNA和e1排除可能会影响转录与多核糖体和翻译。此外，缺乏前两个锌指的e1-缺陷蛋白同种型是高度不稳定的，并且其EGFP融合蛋白具有严重受损的剪接活性。我们还表明，MBNL 1可以从三个不同的启动子转录，转录起始位点决定了E1调控的模式。两者合计，我们表明，MBNL蛋白控制MBNL 1的稳态水平，通过与E1在其前体mRNA的相互作用。我们研究的见解为基于MBNL 1 mRNA转录起始位点和e1剪接的治疗DM开辟了新途径。
Muscleblind-like proteins (MBNLs) are regulators of RNA metabolism. During tissue differentiation the level of MBNLs increases, while their functional insufficiency plays a crucial role in myotonic dystrophy (DM). Deep sequencing of RNA molecules cross-linked to immunoprecipitated protein particles (CLIP-seq) revealed that MBNL1 binds to MBNL1 exon 1 (e1) encoding both the major part of 5΄UTR and an amino-terminal region of MBNL1 protein. We tested several hypotheses regarding the possible autoregulatory function of MBNL1 binding to its own transcript. Our data indicate that MBNLs induce skipping of e1 from precursor MBNL1 mRNA and that e1 exclusion may impact transcript association with polysomes and translation. Furthermore, e1-deficient protein isoform lacking the first two zinc fingers is highly unstable and its EGFP fusion protein has severely compromised splicing activity. We also show that MBNL1 can be transcribed from three different promoters and that the transcription initiation site determines the mode of e1 regulation. Taken together, we demonstrate that MBNL proteins control steady-state levels of MBNL1 through an interaction with e1 in its precursor mRNA. Insights from our study open a new avenue in therapies against DM based on manipulation of the transcription initiation site and e1 splicing of MBNL1 mRNA.