de Boer H, Nomura M
J Biol Chem. 1979 Jul 10;254(13):5609-12.
32P-labeled RNA was isolated from growing Escherichia coli and the 5' end nucleoside triphosphates of rRNA were analyzed after hybridization to various DNA fragments derived from one of the rRNA operons, rrnE. The results show that there are two transcription start sites for each rRNA operon in vivo, one initiating with ATP (or GTP), and the second initiating with CTP. Transcription from the first site was observed to be stronger than that from the second site. These two sites correspond to the two promoters identified in the previous in vitro studies, indicating that the two promoters are used in vivo. These results also demonstrate previously unrecognized transcription initiation with CTP in growing E. coli cells.
从生长中的大肠杆菌中分离出用³²P标记的RNA，并将其与源自rrnE（一个rRNA操纵子）的各种DNA片段杂交后，分析rRNA的5'端核苷三磷酸。结果表明，每个rRNA操纵子在体内有两个转录起始位点，一个以ATP（或GTP）起始，另一个以CTP起始。观察到从第一个位点的转录比从第二个位点的转录更强。这两个位点对应于先前体外研究中鉴定的两个启动子，表明这两个启动子在体内被使用。这些结果还证明了在生长中的大肠杆菌细胞中以前未被认识到的以CTP起始的转录。
