The Biological Laboratories, Harvard University, Cambridge Massachusetts 02138.
Proc Natl Acad Sci U S A. 1981 Jun;78(6):3423-7. doi: 10.1073/pnas.78.6.3423.
In the presence of the S polypeptide, maize chloroplast DNA-dependent RNA polymerase preferentially transcribes sequences within the 2200-nucleotide-pair-long maize chloroplast chromosome fragment Eco [unk] from a supercoiled chimeric plasmid cloned in Escherichia coli [Jolly, S. O. & Bogorad, L. (1980) Proc. Natl. Acad. Sci. USA 77, 822-826]. Eco [unk] contains one gene for tRNA(His) and one for a 1.6-kilobase RNA that includes an open reading frame. These two genes overlap by at least a few nucleotides and are transcribed divergently from complementary DNA strands. This indicates possible transcriptional regulation of chloroplast DNA at the nucleotide level. The 5' end of tRNA(His) (G-U-G) isolated from maize chloroplasts is indistinguishable from that of the transcript produced from Eco [unk] in vitro by maize chloroplast DNA-dependent RNA polymerase. This purified system initiates RNA synthesis faithfully and exhibits preference for some chloroplast genes. Maize chloroplast DNA for tRNA(His) lacks the sequence C-C-A at its 3' terminus; it is presumably added post-transcriptionally. Maize tRNA(His) has both prokaryotic and eukaryotic features.
在 S 多肽存在的情况下，玉米叶绿体 DNA 依赖性 RNA 聚合酶优先转录大肠杆菌中克隆的超螺旋嵌合质粒上 Eco[unk]内的序列，Eco[unk]来自 2200 个核苷酸对长的玉米叶绿体染色体片段 [Jolly, S. O. & Bogorad, L. (1980) Proc. Natl. Acad. Sci. USA 77, 822-826]。Eco[unk] 包含一个 tRNA(His)基因和一个包含开放阅读框的 1.6kb RNA 基因。这两个基因至少重叠几个核苷酸，并从互补的 DNA 链上反向转录。这表明叶绿体 DNA 在核苷酸水平上可能受到转录调控。从玉米叶绿体中分离的 tRNA(His)的 5' 端（G-U-G）与玉米叶绿体 DNA 依赖性 RNA 聚合酶在体外从 Eco[unk]产生的转录物的 5' 端无法区分。这个纯化系统忠实地启动 RNA 合成，并对一些叶绿体基因表现出偏好。玉米 tRNA(His) 的叶绿体 DNA 在其 3' 末端缺乏序列 C-C-A；它可能是转录后添加的。玉米 tRNA(His) 具有原核和真核生物的特征。
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