Chang D D, Clayton D A
EMBO J. 1987 Feb;6(2):409-17. doi: 10.1002/j.1460-2075.1987.tb04770.x.
Priming at the mouse mitochondrial origin of heavy-strand DNA replication is effected by transcripts from the light-strand promoter. The transition from RNA synthesis to DNA synthesis occurs at specific locations between 75 and 165 nucleotides downstream from the transcriptional initiation site. We have identified and partially purified an endonucleolytic activity that cleaves RNA accurately near one of these transition sites; this finding implies a role of specific RNA processing in DNA replication. Cleavage products possess 5'-phosphoryl and 3'-hydroxyl termini. Heterologous assays using mouse or human mitochondrial endoribonuclease with substrates containing the sequences of the human or mouse mitochondrial origins of heavy-strand DNA replication suggest that selection of the cleavage site is guided by sequences adjacent to the actual position of cleavage.
小鼠重链DNA复制的线粒体起点处的引发作用受轻链启动子转录本的影响。从RNA合成到DNA合成的转变发生在转录起始位点下游75至165个核苷酸之间的特定位置。我们已经鉴定并部分纯化了一种核酸内切酶活性，该活性在这些转变位点之一附近精确切割RNA；这一发现暗示了特定RNA加工在DNA复制中的作用。切割产物具有5'-磷酸和3'-羟基末端。使用小鼠或人类线粒体核糖核酸酶对含有人类或小鼠重链DNA复制线粒体起点序列的底物进行的异源分析表明，切割位点的选择受切割实际位置相邻序列的引导。
