REPLICATION OF MITOCHONDRIAL-DNA IN MOUSE L CELLS AND THEIR THYMIDINE KINASE-DERIVATIVES - DISPLACEMENT REPLICATION ON A COVALENTLY-CLOSED CIRCULAR TEMPLATE
REPLICATION OF MITOCHONDRIAL-DNA IN MOUSE L CELLS AND THEIR THYMIDINE KINASE-DERIVATIVES - DISPLACEMENT REPLICATION ON A COVALENTLY-CLOSED CIRCULAR TEMPLATE
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DOI：
10.1073/pnas.69.12.3810
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发表时间：
1972-01-01
影响因子：
11.1
通讯作者：
CLAYTON, DA
中科院分区：
文献类型：
--
作者：
ROBBERSO.DL;CLAYTON, DA
小鼠L细胞的胸苷激酶系仅将胸苷掺入线粒体DNA中。这一事实允许在溴化乙锭-氯化铯梯度中评估标记的线粒体DNA组分。污染的核DNA是未标记的，不需要被去除。去除纯化的线粒体的DNA酶处理揭示了展示置换复制直至全基因组大小的复制形式是共价闭合的环状分子。变性后，这些较大的复制分子的短暂复性产生了封闭的环状DNA，缺乏沃森-克里克转角，表现为单链环。该结果表明，置换复制随着共价闭合的环状模板的切口和快速闭合而进行。
Thymidine kinase-lines of mouse L cells incorporate thymidine exclusively into mitochondrial DNA. This fact permits assessment of labeled mitochondrial DNA components in ethidium bromide-cesium chloride gradients. Contaminating nuclear DNA is unlabeled and need not be removed. Elimination of the DNase treatment of purified mitochondria reveals that the replicative forms that exhibit displacement replication up to full genome size are covalently-closed circular molecules. Denaturation followed by brief renaturation of these larger replicating molecules produces closed-circular DNA with a deficiency of Watson-Crick turns, appearing as single-strand loops. This result suggests that displacement replication proceeds with nicking and rapid closure of the covalently-closed circular template.