Ultra-deep sequencing of mouse mitochondrial DNA: mutational patterns and their origins.
Ultra-deep sequencing of mouse mitochondrial DNA: mutational patterns and their origins.
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DOI：
10.1371/journal.pgen.1002028
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发表时间：
2011-03
期刊：
影响因子：
4.5
通讯作者：
Gyllensten U
中科院分区：
文献类型：
--
作者：
Ameur A;Stewart JB;Freyer C;Hagström E;Ingman M;Larsson NG;Gyllensten U
线粒体DNA的体细胞突变与衰老过程有关，但目前还没有普遍接受的方法对其进行准确的定量。我们已经使用超深度测序来研究正常和早熟小鼠肝脏中的全基因组mtDNA突变负荷。对于表达校正缺陷型mtDNA聚合酶的等位基因纯合子小鼠（mtDNA突变小鼠），其点突变负荷比其野生型同胞高10倍。此外，mtDNA突变小鼠的截短线性mtDNA分子水平增加，导致缺失区域的序列覆盖率降低。相比之下，在mtDNA突变小鼠中，具有大缺失的环状mtDNA分子发生的频率极低，因此不能驱动过早衰老表型。序列分析表明，在杂合子mtDNA突变小鼠和它们的野生型同胞中，突变负荷的主要比例是从它们的杂合子母亲遗传而来的，这与种系传播一致。我们发现野生型C57 Bl/6 N小鼠的点突变或缺失水平没有随着年龄的增加而增加，因此质疑这些变化在衰老中的致病作用。此外，在任何研究的基因型中，颠换突变的频率都没有随着时间的推移而增加，这与氧化损伤作为mtDNA突变的主要原因有关。因此，我们对小鼠的研究结果表明，大多数体细胞mtDNA突变是在发育过程中发生的复制错误，而不是成年期损伤积累的结果。线粒体代表细胞的动力室，并有自己的DNA。线粒体基因组中的突变与一系列人类疾病有关，也被认为是衰老过程背后的驱动力。我们使用超深度测序研究了正常近交系小鼠和表达导致过早衰老的校正缺陷型mtDNA聚合酶的小鼠（mtDNA突变小鼠）肝脏线粒体DNA（mtDNA）的全基因组突变负荷。mtDNA突变小鼠的点突变随着年龄的增长而急剧增加，其点突变水平比野生型同胞或正常C57 Bl/6 N小鼠高10倍。在mtDNA突变小鼠中，环状mtDNA大缺失分子的发生频率非常低，因此不太可能导致过早衰老表型。我们发现正常小鼠的点突变或缺失水平没有随着年龄的增加而增加，这与mtDNA突变的积累导致衰老的观点相反。我们的研究结果表明，大多数体细胞mtDNA突变发生在胚胎发生过程中的mtDNA快速扩增的复制错误，并没有造成损害积累在成年生活。
Somatic mutations of mtDNA are implicated in the aging process, but there is no universally accepted method for their accurate quantification. We have used ultra-deep sequencing to study genome-wide mtDNA mutation load in the liver of normally- and prematurely-aging mice. Mice that are homozygous for an allele expressing a proof-reading–deficient mtDNA polymerase (mtDNA mutator mice) have 10-times-higher point mutation loads than their wildtype siblings. In addition, the mtDNA mutator mice have increased levels of a truncated linear mtDNA molecule, resulting in decreased sequence coverage in the deleted region. In contrast, circular mtDNA molecules with large deletions occur at extremely low frequencies in mtDNA mutator mice and can therefore not drive the premature aging phenotype. Sequence analysis shows that the main proportion of the mutation load in heterozygous mtDNA mutator mice and their wildtype siblings is inherited from their heterozygous mothers consistent with germline transmission. We found no increase in levels of point mutations or deletions in wildtype C57Bl/6N mice with increasing age, thus questioning the causative role of these changes in aging. In addition, there was no increased frequency of transversion mutations with time in any of the studied genotypes, arguing against oxidative damage as a major cause of mtDNA mutations. Our results from studies of mice thus indicate that most somatic mtDNA mutations occur as replication errors during development and do not result from damage accumulation in adult life. Mitochondria represent the powerhouses of cells and have their own DNA. Mutations in the mitochondrial genome are associated with a range of human diseases and have also been implicated as a driving force behind the aging process. We have used ultra-deep sequencing to study the genome-wide mutation load in the mitochondrial DNA (mtDNA) of liver from normal inbred mice and mice that express a proof-reading–deficient mtDNA polymerase (mtDNA mutator mice) that cause premature aging. The mtDNA mutator mice show a dramatic increase of point mutations with age and have 10-times-higher point mutation levels than wildtype siblings or normal C57Bl/6N mice. Circular mtDNA molecules with large deletions occur at very low frequencies in mtDNA mutator mice and are therefore unlikely to contribute to the premature aging phenotype. We found no increase in levels of point mutations or deletions in normal mice with increasing age, arguing against the accumulation of mtDNA mutations as contributing to aging. Our results indicate that most somatic mtDNA mutations occur as replication errors during the rapid amplification of mtDNA during embryogenesis and do not result from damage accumulation in adult life.
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影响因子：
14.9
作者：
CORTOPASSI, GA;ARNHEIM, N
通讯作者：
ARNHEIM, N
影响因子：
64.5
作者：
Chen H;Vermulst M;Wang YE;Chomyn A;Prolla TA;McCaffery JM;Chan DC
通讯作者：
Chan DC
DOI：
10.1111/j.1532-5415.1972.tb00787.x
发表时间：
1972-01-01
影响因子：
6.3
作者：
HARMAN, D
通讯作者：
HARMAN, D
DOI：
10.1016/0006-291x(90)90497-b
发表时间：
1990-08-16
影响因子：
3.1
作者：
IKEBE, S;TANAKA, M;OZAWA, T
通讯作者：
OZAWA, T
影响因子：
5.3
作者：
SCHWARZE, SR;LEE, CM;AIKEN, JM
通讯作者：
AIKEN, JM