A potential stem-loop structure and the sequence CAAUCAA in the transcript are insufficient to signal rho-dependent transcription termination at lambda tR1.
A potential stem-loop structure and the sequence CAAUCAA in the transcript are insufficient to signal rho-dependent transcription termination at lambda tR1.
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转录本中潜在的茎环结构和序列 CAAUCAA 不足以发出 lambda tR1 处 rho 依赖性转录终止的信号。
DOI：
10.1093/nar/12.2.1287
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发表时间：
1984
影响因子：
14.9
通讯作者：
Narang,SA
中科院分区：
文献类型：
--
作者：
Lau,LF;Roberts,JW;Wu,R;Georges,F;Narang,SA
有人认为，RNA转录物中可以形成茎环结构的序列，随后是序列CAAUCAA，是ρ依赖性转录终止的信号。我们通过合成一个DNA双链体来验证这一假设，该DNA双链体的序列对应于λ tR1终止子中包含这些结构特征的区域。我们克隆了在lacUV5启动子控制下的这个合成的DNA片段，并表明它在合成序列的体外转录过程中不会引起ρ依赖性的终止，尽管效率低于λ模板上的相应序列。即使在延长合成位点处的转录暂停的条件下也没有检测到ρ介导的终止，表明合成序列作为转录物释放位点是有缺陷的。我们认为，与ρ非依赖性终止子不同，ρ依赖性终止子需要除了终止位点之前的序列之外的序列。
It has been suggested that a sequence in the RNA transcript that can form a stem and loop structure, followed by the sequence CAAUCAA, is the signal for ρ-dependent transcription termination. We tested this hypothesis by synthesizing a DNA duplex whose sequence corresponds to a region of the λtR1terminator that contains these structural features. We cloned this synthehc DNA fragment under the control of thelacUV5 promoter, and showed that it does not cause ρ-dependent terminationinvitroRNA polymerase pauses duringinvitrotranscription across the synthetic sequence, although less efficiently than at the corresponding sequence on the λ template. No ρ-mediated termination was detected even under conditions that prolonged transcriptional pausing at the synthetic site, indicating that the synthetic sequence is defective as a transcript release site. We suggest that unlike ρ-independent terminators, ρ-dependent terminators require sequences in addition to those immediately before the sites of termination.