Chang D D, Hauswirth W W, Clayton D A
EMBO J. 1985 Jun;4(6):1559-67. doi: 10.1002/j.1460-2075.1985.tb03817.x.
Mammalian mitochondrial DNA maintains a novel displacement-loop region containing the major sites of transcriptional initiation and the origin of heavy strand DNA replication. Because the exact map positions of the 5' termini of nascent mouse displacement-loop strands are known, it is possible to examine directly a potential relationship between replication priming and transcription. Analyses of in vivo nucleic acids complementary to the displacement-loop region reveal two species with identical 5' ends at map position 16 183. One is entirely RNA and the other is RNA covalently linked to DNA. In the latter the transition from RNA to DNA is sharp, occurring near or within a series of previously identified conserved sequences 74-163 nucleotides downstream from the transcriptional initiation site. These data suggest that the initial events in replication priming and transcription are the same and that the decision to synthesize DNA or RNA is a downstream event under the control of short, conserved displacement-loop template sequences.
哺乳动物线粒体DNA保留了一个新的置换环区域，该区域包含转录起始的主要位点和重链DNA复制的起点。由于新生小鼠置换环链5'末端的确切图谱位置是已知的，因此有可能直接研究复制引发与转录之间的潜在关系。对与置换环区域互补的体内核酸的分析揭示了两种在图谱位置16183处具有相同5'末端的分子。一种完全是RNA，另一种是与DNA共价连接的RNA。在后者中，从RNA到DNA的转变很明显，发生在转录起始位点下游74 - 163个核苷酸的一系列先前确定的保守序列附近或之内。这些数据表明，复制引发和转录的初始事件是相同的，并且合成DNA或RNA的决定是在短的、保守的置换环模板序列控制下的下游事件。
