Deletion of Gtpbp3 in zebrafish revealed the hypertrophic cardiomyopathy manifested by aberrant mitochondrial tRNA metabolism
Deletion of Gtpbp3 in zebrafish revealed the hypertrophic cardiomyopathy manifested by aberrant mitochondrial tRNA metabolism
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DOI：
10.1093/nar/gkz218
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发表时间：
2019-06-04
影响因子：
14.9
通讯作者：
Guan, Min-Xin
中科院分区：
文献类型：
--
作者：
Chen, Danni;Zhang, Zengming;Guan, Min-Xin
GTPBP 3是一种高度保守的tRNA修饰酶，用于在线粒体tRNA（Glu）、tRNA（Gln）、tRNA（Lys）、tRNA（Trp）和tRNA（Leu（UUR））的摆动位置生物合成m（5）U。既往研究表明GTPBP 3基因突变与肥厚型心肌病（HCM）相关。然而，GTPBP 3缺乏症的病理生理学仍然是难以捉摸的。利用CRISPR/Cas9系统产生的gtpbp 3基因敲除斑马鱼，我们证明了gtpbp 3基因敲除斑马鱼的线粒体tRNA代谢异常。gtpbp 3的缺失可能改变tRNA的功能性折叠，这通过tRNA（Glu）、tRNA（Lys）、tRNA（Trp）和tRNA（Leu（UUR））的构象变化和对S1介导的消化的敏感性来指示。引人注目的是，gtpbp 3基因敲除的斑马鱼表现出线粒体tRNA氨酰化效率的整体增加。异常的线粒体tRNA代谢损害线粒体翻译，产生蛋白质稳态应激并改变呼吸链复合物的活性。这些线粒体功能障碍导致胚胎心脏发育的改变，并减少了突变斑马鱼心室缩短的分数。值得注意的是，gtpbp 3基因敲除的斑马鱼表现出心肌细胞肥大和心室心肌纤维紊乱。gtpbp 3敲除斑马鱼中的这些心脏缺陷重现了携带GTPBP 3突变的HCM患者的临床表型。我们的研究结果强调了有缺陷的核苷酸修饰的tRNA在线粒体生物合成及其在肥厚型心肌病中的病理后果的基本作用。
GTPBP3 is a highly conserved tRNA modifying enzyme for the biosynthesis of m(5)U at the wobble position of mitochondrial tRNA(Glu), tRNA(Gln), tRNA(Lys), tRNA(Trp) and tRNA(Leu(UUR)). The previous investigations showed that GTPBP3 mutations were associated with hypertrophic cardiomyopathy (HCM). However, the pathophysiology of GTPBP3 deficiency remains elusively. Using the gtpbp3 knockout zebrafish generated by CRISPR/Cas9 system, we demonstrated the aberrant mitochondrial tRNA metabolism in gtpbp3 knock-out zebrafish. The deletion of gtpbp3 may alter functional folding of tRNA, indicated by conformation changes and sensitivity to S1-mediated digestion of tRNA(Glu), tRNA(Lys), tRNA(Trp) and tRNA(Leu(UUR)). Strikingly, gtpbp3 knock-out zebrafish displayed the global increases in the aminoacylated efficiencies of mitochondrial tRNAs. The aberrant mitochondrial tRNA metabolisms impaired mitochondrial translation, produced proteostasis stress and altered activities of respiratory chain complexes. These mitochondria dysfunctions caused the alterations in the embryonic heart development and reduced fractional shortening of ventricles in mutant zebrafish. Notably, the gtpbp3 knock-out zebrafish exhibited hypertrophy of cardiomyocytes and myocardial fiber disarray in ventricles. These cardiac defects in the gtpbp3 knock-out zebrafish recapitulated the clinical phenotypes in HCM patients carrying the GTPBP3 mutation(s). Our findings highlight the fundamental role of defective nucleotide modifications of tRNAs in mitochondrial biogenesis and their pathological consequences in hypertrophic cardiomyopathy.