前导肽序列和长度对大肠杆菌色氨酸操纵子衰减调控的影响。
The effects of leader peptide sequence and length on attenuation control of the trp operon of E.coli.
作者信息
Roesser J R, Yanofsky C
机构信息
Department of Biological Sciences, Stanford University, CA 94305-5020.
出版信息
Nucleic Acids Res. 1991 Feb 25;19(4):795-800. doi: 10.1093/nar/19.4.795.
We have examined the effects of changing the length and codon content of the trp leader peptide coding region on expression of the trp operon of Escherichia coli, it had previously been shown that coupling of transcription and translation in the trp leader region is essential for both basal level control and tryptophan starvation control of transcription attenuation in this operon. We have found that increasing the length of the leader peptide coding region by 55 codons allowed normal basal level control and normal tryptophan starvation control. As expected, the presence of a nonsense codon early in the leader peptide coding region decreased basal expression and eliminated starvation control. Introducing tandem rare codons had no effect on basal level expression, but eliminated the tryptophan starvation response. Frameshifting at tandem rare codons was tested as the most likely explanation for loss of the tryptophan starvation response, but the results were inconclusive.
我们已经研究了改变色氨酸前导肽编码区的长度和密码子组成对大肠杆菌色氨酸操纵子表达的影响。此前已有研究表明，色氨酸前导区内转录与翻译的偶联对于该操纵子转录衰减的基础水平控制和色氨酸饥饿控制均至关重要。我们发现，将前导肽编码区的长度增加55个密码子可实现正常的基础水平控制和正常的色氨酸饥饿控制。正如预期的那样，在前导肽编码区早期出现无义密码子会降低基础表达并消除饥饿控制。引入串联稀有密码子对基础水平表达没有影响，但消除了色氨酸饥饿反应。作为色氨酸饥饿反应丧失的最可能解释，我们测试了在串联稀有密码子处的移码情况，但结果尚无定论。
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