TWINKLE is an essential mitochondrial helicase required for synthesis of nascent D-loop strands and complete mtDNA replication.
TWINKLE is an essential mitochondrial helicase required for synthesis of nascent D-loop strands and complete mtDNA replication.
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Twinkle是合成新生D环链和完整mtDNA复制所需的必不可少的线粒体解旋酶。
DOI：
10.1093/hmg/ddt051
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发表时间：
2013-05-15
影响因子：
3.5
通讯作者：
Larsson NG
中科院分区：
文献类型：
--
作者：
Milenkovic D;Matic S;Kühl I;Ruzzenente B;Freyer C;Jemt E;Park CB;Falkenberg M;Larsson NG
哺乳动物线粒体DNA（mtDNA）的复制依赖于最小复制体，其由异源三聚体mtDNA聚合酶（POLG）、六聚体DNA解旋酶TWINKLE和四聚体单链DNA结合蛋白（mtSSB）组成。TWINKLE已被证明在复制过程中解开DNA，许多致病突变已被映射到其基因。携带Twinkle突变的患者会出现mtDNA的多处缺失、呼吸链功能缺陷和神经肌肉症状。尽管它在人类疾病中的重要性，但目前还不清楚TWINKLE是否是哺乳动物线粒体中唯一的复制型DNA解旋酶。此外，相当大一部分mtDNA复制事件在线粒体控制区（D环）的末端过早终止，目前尚不清楚TWINKLE是否也在这种失败的复制中发挥作用。在这里，我们提出了一个有条件的小鼠敲除Twinkle，并证明Twinkle是小鼠胚胎发育所必需的，因此是唯一的复制DNA解旋酶在哺乳动物线粒体。条件性敲除Twinkle导致心脏和骨骼肌中严重和快速的mtDNA耗竭。在Twinkle敲除后没有观察到复制中间体或缺失的mtDNA分子，这表明Twinkle一旦加载是非常进行性的。我们还表明，TWINKLE是必不可少的新生H-链合成的D-环，从而表明，没有单独的DNA解旋酶负责复制该地区。因此，我们的数据表明，相对于完整的mtDNA复制流产的D-环合成水平的调节，并可能提供一种机制，以控制进展到完整的mtDNA复制。
Replication of the mammalian mitochondrial DNA (mtDNA) is dependent on the minimal replisome, consisting of the heterotrimeric mtDNA polymerase (POLG), the hexameric DNA helicase TWINKLE and the tetrameric single-stranded DNA-binding protein (mtSSB). TWINKLE has been shown to unwind DNA during the replication process and many disease-causing mutations have been mapped to its gene. Patients carrying Twinkle mutations develop multiple deletions of mtDNA, deficient respiratory chain function and neuromuscular symptoms. Despite its importance in human disease, it has been unclear whether TWINKLE is the only replicative DNA helicase in mammalian mitochondria. Furthermore, a substantial portion of mtDNA replication events is prematurely terminated at the end of mitochondrial control region (D-loop) and it is unknown whether TWINKLE also has a role in this abortive replication. Here, we present a conditional mouse knockout for Twinkle and demonstrate that TWINKLE is essential for mouse embryonic development and thus is the only replicative DNA helicase in mammalian mitochondria. Conditional knockout of Twinkle results in severe and rapid mtDNA depletion in heart and skeletal muscle. No replication intermediates or deleted mtDNA molecules are observed after Twinkle knockout, suggesting that TWINKLE once loaded is very processive. We also demonstrate that TWINKLE is essential for nascent H-strand synthesis in the D-loop, thus showing that there is no separate DNA helicase responsible for replication of this region. Our data thus suggest that the relative levels of abortive D-loop synthesis versus complete mtDNA replication are regulated and may provide a mechanism to control progression to complete mtDNA replication.
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影响因子：
3.5
作者：
Hance, N;Ekstrand, MI;Trifunovic, A
通讯作者：
Trifunovic, A
影响因子：
29
作者：
Camara, Yolanda;Asin-Cayuela, Jorge;Larsson, Nils-Goran
通讯作者：
Larsson, Nils-Goran
DOI：
10.1006/bbrc.1994.1603
发表时间：
1994-05-16
影响因子：
3.1
作者：
LARSSON, NG;OLDFORS, A;CLAYTON, DA
通讯作者：
CLAYTON, DA
影响因子：
3.5
作者：
Ekstrand, MI;Falkenberg, M;Larsson, NG
通讯作者：
Larsson, NG
影响因子：
5.6
作者：
Korhonen, Jenny A.;Pande, Vineet;Falkenberg, Maria
通讯作者：
Falkenberg, Maria