Overexpression of MTERFD1 or MTERFD3 impairs the completion of mitochondrial DNA replication
Overexpression of MTERFD1 or MTERFD3 impairs the completion of mitochondrial DNA replication
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DOI：
10.1007/s11033-010-0233-9
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发表时间：
2011-02-01
影响因子：
2.8
通讯作者：
Jacobs, Howard T.
中科院分区：
文献类型：
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作者：
Hyvarinen, Anne K.;Pohjoismaki, Jaakko L. O.;Jacobs, Howard T.
线粒体转录终止因子（mTERF）家族的生理作用尚不清楚。MTERF及其同源物影响体外转录读通，但它们在体内调节线粒体RNA水平的程度尚不清楚。此外，MTERF以前被证明可以促进复制暂停。为了测试它们在mtDNA代谢中的作用，我们创建了诱导表达mTERF家族中两个成员MTERFD1和MTERFD3的表位标记版本的细胞系，以及针对这两个成员的shRNA构建物。我们证实了这两种因子的线粒体靶向性和缺乏序列特异性DNA结合。表位标记的MTERFD1或MTERFD3的过表达导致适度的mtDNA拷贝数消耗和特异性mtDNA复制中间体的积累，这表明复制的终端步骤受损。这些发现进一步暗示了mTERF家族抑制复制叉的进展，并支持了它们促进复制和转录机制的有序传递，从而有助于基因组稳定性的观点。
The physiological roles of the mitochondrial transcription termination factor (mTERF) family are poorly understood. MTERF and its homologues influence transcriptional readthrough in vitro, but the extent to which they regulate mitochondrial RNA levels in vivo is unclear. In addition, MTERF was previously shown to promote replication pausing. To test their roles in mtDNA metabolism, we created cell-lines inducibly expressing epitope-tagged versions of two members of the mTERF family, MTERFD1 and MTERFD3, as well as shRNA constructs targeted at each. We confirmed mitochondrial targeting and lack of sequence-specific DNA binding for both factors. Over-expression of epitope-tagged MTERFD1 or MTERFD3 resulted in modest mtDNA copy-number depletion and an accumulation of specific mtDNA replication intermediates indicating an impairment of the terminal steps of replication. These findings further implicate the mTERF family in restraining replication fork progression and support the idea that they facilitate the orderly passage of replication and transcription machineries, thus contributing to genome stability.