McGarvey P, Helling R B, Lee J Y, Engelke D R, el-Gewely M R
Department of Biology, University of Michigan, Ann Arbor 48109.
Curr Genet. 1988 Nov;14(5):493-500. doi: 10.1007/BF00521275.
The site of initiation of chloroplast rRNA synthesis was determined by S1-mapping and by sequencing primary rRNA transcripts specifically labeled at their 5'-end. Transcription initiates at a single site 53 nucleotides upstream of the 5'-end of the mature 16S rRNA under all growth conditions examined. The initiation site is within a DNA sequence that is highly homologous to and probably derived from a tRNA gene-region located elsewhere in the chloroplast genome. A nearly identical sequence (102 of 103 nucleotides) is present near the replication origin. The near identity of the two sequences suggests a common mode for control of transcription of the rRNA genes and initiation of chloroplast DNA replication. The related sequence in the tRNA gene-region does not appear to serve as a transcript initiation site.
通过S1作图以及对在其5'端特异性标记的初级rRNA转录本进行测序，确定了叶绿体rRNA合成的起始位点。在所有检测的生长条件下，转录起始于成熟16S rRNA 5'端上游53个核苷酸处的单个位点。起始位点位于一段与叶绿体基因组其他位置的一个tRNA基因区域高度同源且可能源自该区域的DNA序列内。在复制起点附近存在一个几乎相同的序列（103个核苷酸中的102个）。这两个序列的近乎相同表明rRNA基因转录控制和叶绿体DNA复制起始存在共同模式。tRNA基因区域中的相关序列似乎并非转录起始位点。
