Institute of Cell Biology, University of Bern, Baltzerstrasse 4, 3012 Bern, Switzerland.
Graduate School for Cellular and Biomedical Sciences, University of Bern, Hochschulstrasse 6, 3012 Bern, Switzerland.
FEMS Microbiol Rev. 2023 Nov 1;47(6). doi: 10.1093/femsre/fuac047.
Mitochondrial DNA replication is an essential process in most eukaryotes. Similar to the diversity in mitochondrial genome size and organization in the different eukaryotic supergroups, there is considerable diversity in the replication process of the mitochondrial DNA. In this review, we summarize the current knowledge of mitochondrial DNA replication and the associated factors in trypanosomes with a focus on Trypanosoma brucei, and provide a new model of minicircle replication for this protozoan parasite. The model assumes the mitochondrial DNA (kinetoplast DNA, kDNA) of T. brucei to be loosely diploid in nature and the replication of the genome to occur at two replication centers at the opposing ends of the kDNA disc (also known as antipodal sites, APS). The new model is consistent with the localization of most replication factors and in contrast to the current model, it does not require the assumption of an unknown sorting and transport complex moving freshly replicated DNA to the APS. In combination with the previously proposed sexual stages of the parasite in the insect vector, the new model provides a mechanism for maintenance of the mitochondrial genetic diversity.
线粒体 DNA 复制是大多数真核生物的一个基本过程。与不同真核超群中线粒体基因组大小和组织的多样性相似，线粒体 DNA 的复制过程存在相当大的多样性。在这篇综述中，我们总结了真核生物线粒体 DNA 复制及其相关因素的最新知识，重点是布氏锥虫，并为这种原生动物寄生虫提供了一个新的微环复制模型。该模型假设布氏锥虫的线粒体 DNA（动基体 DNA，kDNA）本质上是松散的二倍体，基因组的复制发生在 kDNA 盘的相对两端的两个复制中心（也称为对端位点，APS）。新模型与大多数复制因子的定位一致，与当前模型相反，它不需要假设一个未知的分拣和运输复合物将新复制的 DNA 移动到 APS。结合寄生虫在昆虫媒介中的先前提出的有性阶段，新模型为维持线粒体遗传多样性提供了一种机制。
