RESTORATION OF A TRANSLATIONAL STOP-START OVERLAP REINSTATES TRANSLATIONAL COUPLING IN A MUTANT TRPB'-TRPA GENE PAIR OF THE ESCHERICHIA-COLI TRYPTOPHAN OPERON
RESTORATION OF A TRANSLATIONAL STOP-START OVERLAP REINSTATES TRANSLATIONAL COUPLING IN A MUTANT TRPB'-TRPA GENE PAIR OF THE ESCHERICHIA-COLI TRYPTOPHAN OPERON
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DOI：
10.1093/nar/17.22.9333
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发表时间：
1989-11-25
影响因子：
14.9
通讯作者：
YANOFSKY, C
中科院分区：
文献类型：
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作者：
DAS, A;YANOFSKY, C
大肠杆菌Trp多顺反子基因的trpB和trpa编码区由重叠的翻译终止密码子和起始密码子分开。TRPA编码区的有效翻译受到翻译耦合的影响，即最大TRPA表达取决于trpB编码区(1，2)的先前翻译。以前的研究表明，TRPA Shine-Dalgarno序列(在trpB内)和/或trpB终止密码子的位置影响TRPA的表达(2)。为了具体检测终止密码子位置的影响，我们构建了保留TRPA起始密码子之前不同核苷酸序列的质粒，只改变了阅读框架。当trpB翻译在野生型阅读框中终止于正常的trpB终止密码子时，TRPA多肽水平高于在天然trpB终止密码子之前或之后停止翻译时的水平。因此，trpB终止密码子与TRPA起始密码子的接近程度显著影响TRPA的表达。
The trpB and trpA coding regions of the polycistronic trp mRNA of Escherichia coli are separated by overlapping translation stop and start codons. Efficient translation of the trpA coding region is subject to translation coupling, i.e., maximal trpA expression is dependent on prior translation of the trpB coding region (1,2). Previous studies demonstrated that the trpA Shine-Dalgarno sequence (within trpB) and/or the location of the trpB stop codon influenced trpA expression (2). To examine the effect of stop codon location specifically, we constructed plasmids in which different nucleotide sequences preceding the trpA start codon were retained, and only the reading frame was changed. When trpB translation proceeded in the wild type reading frame was terminated at the normal trpB stop codon, trpA polypeptide levels were elevated over the levels observed when translation stopped before or after the natural trpB stop codon. The proximity of the trpB stop codon to the trpA start codon therefore markedly influences trpA expression.