Sequence homology between mitochondrial DNAs of different eukaryotes.
Sequence homology between mitochondrial DNAs of different eukaryotes.
复制标题
不同真核生物线粒体 DNA 之间的序列同源性。
DOI：
10.1021/bi00681a002
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发表时间：
1975
期刊：
影响因子：
2.9
通讯作者：
M. Rabinowitz
中科院分区：
文献类型：
--
作者：
S. Jakovcic;J. Casey;M. Rabinowitz
用DNA-DNA杂交法研究了大鼠、小鼠、豚鼠、猴和鸡的线粒体DNA(MtDNA)序列差异。通过碘化丙啶-氯化铯离心法将mtDNA分离为闭合环状分子，体外用大肠杆菌DNA聚合酶I标记mtDNA，并在2500倍的异源mtDNA存在下复性(TM-35度)。用羟基磷灰石柱层析分离单链和双链DNA。用羟基磷灰石柱上的热洗脱色谱比较了杂双链和同双链的热稳定性。在小鼠、豚鼠、猴子和鸡中，与过量2500倍的rar线粒体DNA之间的异源双链形成率分别为70%、59%、37%和22%。在相互杂交中也观察到了类似的结果，其中另一种mtDNA过量存在。与同源双链相比，异源双链的te50降低了18-24度，这表明所有异源杂交体的序列都有相当大的不匹配。当过量驱动DNA与[~3H]mtDNA的浓度比在1250~7500之间变化时，异源双链的形成没有明显的变化。此外，在第一次反应完成后，用多余的驱动DNA进行第二次复性，没有检测到异源双链形成的增加。相似的序列似乎在不同的生物体中优先保守，因为两个不同的异源mtDNA的存在过量导致异源双链形成只有温和的和非相加的增加。线粒体DNA序列的进化分化似乎以与独特序列核DNA相似的速度发生。
The sequence divergence of mitochondrial DNAs (mtDNA) from rat, mouse, guinea pig, monkey, and chicken has been examined by DNA-DNA hybridization. mtDNAs, isolated as closed circular molecules by propidium iodide-CsCl centrifugation, were labeled in vitro by use of Escherichia coli DNA polymerase I, and renatured (Tm-35 degrees) in the presence of a 2500-fold excess of heterologous mtDNA. Single-stranded and duples DNA were separated by hydroxylapatite chromatography. The thermal stability of heteroduplexes was compared to the homoduplex by thermal elution chromatography on hydroxylapatite columns. Heteroduplex fromation between the tritiated myDNAs and a 2500-fole excess of rar mtDNA were 70, 59, 37, and 22%, respectively, for mouse, guinea pig, monkey, and chicken. Similar results were obrained in reciprocal hybridizations where one of the other mtDNAs was present in excess. Considerable mismatching of sequences in all the heterohybrids was indicated by a 18-24 degrees depression in the te50 of the heteroduplexes compared with the homoduplex. There was no apparent change in heteroduplex formation when the concentration ratio of driving DNA in excess to [3H]mtDNA was varied between 1250 and 7500. Furthermore, a second renaturation with excess driving DNA after completion of the first reaction resulted in no detectable augmenting of heteroduplex formation. Similar sequences appear to be conserved preferentially in different organisms, since the presence of two of fouf different heterologous mtDNAs in excess resulted in only moderate and nonadditive increases in heteroduplex formation. Evolutionary divergence of mtDNA sequences appears to have occurred at rates similar to that for unique sequences nuclear DNA.