Mitochondrial DNA transfer to the nucleus generates extensive insertion site variation in maize
Mitochondrial DNA transfer to the nucleus generates extensive insertion site variation in maize
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DOI：
10.1534/genetics.107.079624
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发表时间：
2008-01-01
期刊：
影响因子：
3.3
通讯作者：
Newton, Kathleen J.
中科院分区：
文献类型：
--
作者：
Lough, Ashley N.;Roark, Leah M.;Newton, Kathleen J.
线粒体DNA（mtDNA）插入到核染色体中已经在许多真核生物中被记录。我们利用荧光原位杂交技术（FISH）检测了玉米线粒体DNA插入片段的变异。将代表570-kb玉米线粒体基因组的20个重叠的染色体分别标记并与B73自交系的根尖中期染色体杂交。使用这种方法可以检测到9条染色体上至少15个线粒体DNA插入位点。染色体臂9 L上的着丝粒附近的一个位点被大多数的染色体所识别。为了检查核线粒体DNA序列（NUMTs）中的变异，将标记的Cosmetic的混合物应用于十个不同的近交系的染色体扩散：A188、A632、B37、B73、BMS、KYS、Mo 17、Oh 43、W22和W23。可检测NUMT的数量在品系之间变化很大。除B73外，其余供试自交系在9 L上均未显示出强的杂交信号，表明B73在9 L上存在最近的mtDNA插入。对不同来源的B73和W23自交系内NUMT变异进行了检测。差异是可检测的，这表明线粒体DNA正在被纳入或从玉米核基因组中不断丢失。结果表明，mtDNA插入是核染色体变异的主要来源。
Mitochondrial DNA (mtDNA) insertions into nuclear chromosomes have been documented in a number of eukaryotes. We used fluorescence in situ hybridization (FISH) to examine the variation of mtDNA insertions in maize. Twenty overlapping cosmids, representing the 570-kb maize mitochondrial genome, were individually labeled and hybridized to root tip metaphase chromosomes front the B73 inbred line. A minimum of 15 mtDNA insertion sites on nine chromosomes were detectable using this method. One site near the centromere on chromosome arm 9L was identified by a majority of the cosmids. To examine variation in nuclear mitochondrial DNA sequences (NUMTs), a mixture of labeled cosmids was applied to chromosome spreads of ten diverse inbred lines: A188, A632, B37, B73, BMS, KYS, Mo17, Oh43, W22, and W23. The number of detectable NUMTs varied dramatically among the lines. None of the tested inbred lines other than B73 showed the strong hybridization signal on 9L, suggesting that there is a recent mtDNA insertion at this site in B73. Different sources of B73 and W23 were examined for NUMT variation within inbred lines. Differences were detectable, suggesting either that mtDNA is being incorporated or lost from the maize nuclear genome continuously. The results indicate that mtDNA insertions represent a major source of nuclear chromosomal variation.