Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA.
Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia.
Mitochondrion. 2018 Jan;38:17-22. doi: 10.1016/j.mito.2017.07.009. Epub 2017 Aug 1.
Conventional DNA replication is initiated from specific origins and requires the synthesis of RNA primers for both the leading and lagging strands. In contrast, the replication of yeast mitochondrial DNA is origin-independent. The replication of the leading strand is likely primed by recombinational structures and proceeded by a rolling circle mechanism. The coexistent linear and circular DNA conformers facilitate the recombination-based initiation. The replication of the lagging strand is poorly understood. Re-evaluation of published data suggests that the rolling circle may also provide structures for the synthesis of the lagging-strand by mechanisms such as template switching. Thus, the coupling of recombination with rolling circle replication and possibly, template switching, may have been selected as an economic replication mode to accommodate the reductive evolution of mitochondria. Such a replication mode spares the need for conventional replicative components, including those required for origin recognition/remodelling, RNA primer synthesis and lagging-strand processing.
传统的 DNA 复制是从特定的起始点开始的，需要为前导链和滞后链合成 RNA 引物。相比之下，酵母线粒体 DNA 的复制是无起始点的。前导链的复制可能由重组结构引发，并通过滚环机制进行。同时存在的线性和环状 DNA 构象有利于基于重组的起始。滞后链的复制则知之甚少。对已发表数据的重新评估表明，滚环也可能通过模板转换等机制为滞后链的合成提供结构。因此，将重组与滚环复制相结合，并可能与模板转换相结合，可能被选为一种经济的复制模式，以适应线粒体的简化进化。这种复制模式不需要传统的复制成分，包括那些用于起始识别/重编程、RNA 引物合成和滞后链加工的成分。
