Running on empty: Mitochondria without mtDNA exhibit differential motility and connectivity

Abstract

Plant mitochondria are in continuous motion. While providing ATP to other cellular processes, they also constantly consume ATP to move rapidly within the cell. This movement is in part related to taking up, converting and delivering metabolites and energy to and from different parts of the cell. Plant mitochondria have varying amounts of DNA even within a single cell, from none to the full mitochondrial genome. Because mitochondrial dynamics are altered in an Arabidopsis mutant with disrupted DNA maintenance, we hypothesised that exchanging DNA templates for repair is one of the functions of their movement and interactions. Here, we image mitochondrial DNA by two distinct methods while tracking mitochondrial position to investigate differences in the behaviour of mitochondria with and without DNA in Arabidopsis thaliana . In addition to staining mitochondrial DNA with SYBR Green, we have developed and implemented a fluorescent mitochondrial DNA binding protein that will also enable future understanding of mitochondrial dynamics, genome maintenance and replication. We demonstrate that mitochondria without mtDNA have altered physical behaviour and have a lower immediate connectivity to the rest of the population, further supporting a link between the physical and genetic dynamics of these complex organelles.

Plant phenotyping relevance

植物ミトコンドリアのDNA可視化と位置追跡を中心に、蛍光DNA結合タンパク質を開発・実装し、ミトコンドリアの挙動と接続性という細胞内植物状態を定量化しているため。

Code and data availability

The paper states that all code, videos (.avi time-lapse collections), and plasmid sequences are available at github.com/jo-c-bio/physical-genetic-dynamics, which is a paper-specific public repository. However, this URL is not among the allowed_urls, so no asset can be listed with a valid actionable URL.

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