Discovery of Cyanophage Genomes Which Contain Mitochondrial DNA Polymerase
Discovery of Cyanophage Genomes Which Contain Mitochondrial DNA Polymerase
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DOI：
10.1093/molbev/msr041
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发表时间：
2011-08-01
影响因子：
10.7
通讯作者：
Clokie, Martha R. J.
中科院分区：
文献类型：
--
作者：
Chan, Yi-Wah;Mohr, Remus;Clokie, Martha R. J.
DNA聚合酶γ是真核生物中负责线粒体DNA复制的A家族DNA聚合酶。DNA聚合酶γ的起源仍然难以捉摸，因为它不存在于任何已知的细菌中，尽管人们假设线粒体可能通过噬菌体介导的非直系同源置换继承了该酶。在这里，我们提出了一个分析的两个全长同源基因，这是发现在基因组中的两个噬菌体，其中感染的叶绿素-d含有蓝藻Acaryochloris marina。这些噬菌体DNA聚合酶γ蛋白的系统发育分析表明，它们在DNA聚合酶γ进化枝内深深地分支，因此与它们的真核同源物共享共同的起源。我们还发现了这些噬菌体聚合酶的同源物在环境社区网络基础设施的先进微生物生态学研究和分析（CAMERA）数据库，这属于同一分支。对含有环境同系物的CAMERA组件以及过滤器级分元数据的分析表明，这些组件中的一些可能是细菌来源的。我们还表明，噬菌体编码的DNA聚合酶γ是高度转录的噬菌体基因组复制。这些发现提供了可能有助于重建线粒体进化的数据。
DNA polymerase gamma is a family A DNA polymerase responsible for the replication of mitochondrial DNA in eukaryotes. The origins of DNA polymerase gamma have remained elusive because it is not present in any known bacterium, though it has been hypothesized that mitochondria may have inherited the enzyme by phage-mediated nonorthologous displacement. Here, we present an analysis of two full-length homologues of this gene, which were found in the genomes of two bacteriophages, which infect the chlorophyll-d containing cyanobacterium Acaryochloris marina. Phylogenetic analyses of these phage DNA polymerase gamma proteins show that they branch deeply within the DNA polymerase gamma clade and therefore share a common origin with their eukaryotic homologues. We also found homologues of these phage polymerases in the environmental Community Cyberinfrastructure for Advanced Microbial Ecology Research and Analysis (CAMERA) database, which fell in the same clade. An analysis of the CAMERA assemblies containing the environmental homologues together with the filter fraction metadata indicated some of these assemblies may be of bacterial origin. We also show that the phage-encoded DNA polymerase gamma is highly transcribed as the phage genomes are replicated. These findings provide data that may assist in reconstructing the evolution of mitochondria.