Sorting of mitochondrial and plastid heteroplasmy in Arabidopsis is extremely rapid and depends on MSH1 activity.
Sorting of mitochondrial and plastid heteroplasmy in Arabidopsis is extremely rapid and depends on MSH1 activity.
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DOI：
10.1073/pnas.2206973119
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发表时间：
2022-08-23
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
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线粒体和质体在真核生物中起着重要作用;因此，它们基因组的突变可能会产生严重的后果。在动物中，早期的生殖系隔离产生了遗传瓶颈，在线粒体突变中提供了细胞与细胞的差异，选择可以发挥作用。然而，植物和其他缺乏早期生殖系分离的生物体中细胞器突变的动态仍然不清楚。在这里，我们表明，植物细胞器基因组中的突变排序进展迅速，比动物快得多。在线粒体中，这一过程被MutS同系物1（MSH 1）加速，这是一种参与细胞器基因组重组和修复的基因。这表明在植物中，重组修复在细胞器突变频率上产生细胞与细胞之间的差异，从而在没有经典的种系瓶颈的情况下促进选择。新的线粒体和质体突变的命运取决于它们在细胞内众多细胞器基因组拷贝中持续和传播的能力（异质性）。异质性在多大程度上跨代传递或通过遗传瓶颈消除，在植物中还没有很好的理解，部分原因是它们的低突变率使这些变异如此罕见。MutS同源物1（MSH 1），一个参与植物细胞器DNA修复的基因的破坏，导致许多从头点突变，我们用来定量跟踪拟南芥线粒体和质体基因组中单核苷酸变异的遗传。我们发现，异质分选（固定或丢失的变体）是快速的两个细胞器，大大超过在动物中观察到的速率。在msh 1突变体中，质体变体比线粒体中的变体分选得更快，并且通常在一代内固定或丢失。质体和线粒体的有效传输瓶颈尺寸（N）分别为N = 1和4。恢复MSH 1功能进一步增加了线粒体中异质分选的速率（N = 1.3），这可能是因为它在促进基因转换中的假设作用，作为DNA修复的机制，预计将使细胞内的基因组拷贝均匀化。异质分选也有利于GC碱基对。因此，植物细胞器基因组中的重组修复和基因转换可以潜在地加速异质性的消除，并使这种分选过程的结果产生偏差。
Mitochondria and plastids play essential roles in eukaryotic life; thus, mutations in their genomes can have severe consequences. In animals, early germline sequestration creates genetic bottlenecks, providing cell-to-cell variance in mitochondrial mutations upon which selection can act. However, the dynamics of organellar mutations in plants and other organisms that lack early germline segregation remain unclear. Here, we show that sorting of mutations in plant organellar genomes proceeds rapidly, much faster than in animals. In mitochondria, this process is accelerated by MutS Homolog 1 (MSH1), a gene involved in recombination and repair of organellar genomes. This suggests that in plants, recombinational repair creates cell-to-cell variance in the frequency of organellar mutations, facilitating selection in the absence of a classic germline bottleneck. The fate of new mitochondrial and plastid mutations depends on their ability to persist and spread among the numerous organellar genome copies within a cell (heteroplasmy). The extent to which heteroplasmies are transmitted across generations or eliminated through genetic bottlenecks is not well understood in plants, in part because their low mutation rates make these variants so infrequent. Disruption of MutS Homolog 1 (MSH1), a gene involved in plant organellar DNA repair, results in numerous de novo point mutations, which we used to quantitatively track the inheritance of single nucleotide variants in mitochondrial and plastid genomes in Arabidopsis. We found that heteroplasmic sorting (the fixation or loss of a variant) was rapid for both organelles, greatly exceeding rates observed in animals. In msh1 mutants, plastid variants sorted faster than those in mitochondria and were typically fixed or lost within a single generation. Effective transmission bottleneck sizes (N) for plastids and mitochondria were N ∼ 1 and 4, respectively. Restoring MSH1 function further increased the rate of heteroplasmic sorting in mitochondria (N ∼ 1.3), potentially because of its hypothesized role in promoting gene conversion as a mechanism of DNA repair, which is expected to homogenize genome copies within a cell. Heteroplasmic sorting also favored GC base pairs. Therefore, recombinational repair and gene conversion in plant organellar genomes can potentially accelerate the elimination of heteroplasmies and bias the outcome of this sorting process.
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影响因子：
7.7
作者：
Colnaghi M;Pomiankowski A;Lane N
通讯作者：
Lane N
影响因子：
10.7
作者：
Christie, Joshua R.;Beekman, Madeleine
通讯作者：
Beekman, Madeleine
影响因子：
30.8
作者：
Cree, Lynsey M.;Samuels, David C.;Chinnery, Patrick F.
通讯作者：
Chinnery, Patrick F.
避免有或没有种系瓶颈的真核生物的细胞器突变崩溃。
影响因子：
9.8
作者：
Edwards DM;Røyrvik EC;Chustecki JM;Giannakis K;Glastad RC;Radzvilavicius AL;Johnston IG
通讯作者：
Johnston IG
DOI：
10.1073/pnas.2118740119
发表时间：
2022-04-12
影响因子：
11.1
作者：
通讯作者：
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