Mitochondrial DNA, chloroplast DNA and the origins of development in eukaryotic organisms
Mitochondrial DNA, chloroplast DNA and the origins of development in eukaryotic organisms
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DOI：
10.1186/1745-6150-5-42
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发表时间：
2010-06-29
期刊：
影响因子：
5.5
通讯作者：
Bendich, Arnold J.
中科院分区：
文献类型：
--
作者：
Bendich, Arnold J.
背景：已经提出了几个建议来解释多细胞生命形式的兴起。内部环境可以被创造和控制，生殖细胞可以在新的结构中得到保护，增加的生物体大小允许细胞类型之间的“劳动分工”。这些建议描述了多细胞生物体相对于单细胞生物体在组织水平上或高于单个细胞的优势。我专注于进化的后续阶段，当多细胞生物开始发展的过程，后来成为更复杂的胚胎发育在动物和植物中发现。假设：线粒体和叶绿体中DNA的极端不稳定性并没有得到广泛的重视，尽管它在四十年前就被首次报道。在这里，我表明，多细胞动物和植物的进化成功可以追溯到细胞器DNA的保护。设想了三个阶段。隔离允许线粒体和叶绿体被放置在“安静”的生殖系细胞中，使得它们的DNA不暴露于“活跃”体细胞中这些细胞器产生的氧化应激。这一优势随后提供了机会，在此期间，细胞内和细胞间的信号传导以及（在动物中）细胞-细胞识别分子进化的新过程出现了。发展，然后导致了动物和plants.Implications的巨大多样性：体干细胞的潜能是其产生细胞类型以外的本身，这是一个系统的属性。从细胞群体中出现干细胞所需的生化特性之一可能是保护细胞器DNA免受氧化应激的代谢静止。
Background: Several proposals have been made to explain the rise of multicellular life forms. An internal environment can be created and controlled, germ cells can be protected in novel structures, and increased organismal size allows a "division of labor" among cell types. These proposals describe advantages of multicellular versus unicellular organisms at levels of organization at or above the individual cell. I focus on a subsequent phase of evolution, when multicellular organisms initiated the process of development that later became the more complex embryonic development found in animals and plants. The advantage here is realized at the level of the mitochondrion and chloroplast.Hypothesis: The extreme instability of DNA in mitochondria and chloroplasts has not been widely appreciated even though it was first reported four decades ago. Here, I show that the evolutionary success of multicellular animals and plants can be traced to the protection of organellar DNA. Three stages are envisioned. Sequestration allowed mitochondria and chloroplasts to be placed in "quiet" germ line cells so that their DNA is not exposed to the oxidative stress produced by these organelles in "active" somatic cells. This advantage then provided Opportunity, a period of time during which novel processes arose for signaling within and between cells and (in animals) for cell-cell recognition molecules to evolve. Development then led to the enormous diversity of animals and plants.Implications: The potency of a somatic stem cell is its potential to generate cell types other than itself, and this is a systems property. One of the biochemical properties required for stemness to emerge from a population of cells might be the metabolic quiescence that protects organellar DNA from oxidative stress.