Ivanov I, Alexandrova R, Dragulev B, Saraffova A, AbouHaidar M G
Department of Botany, University of Toronto, Ontario, Canada.
FEBS Lett. 1992 Jul 28;307(2):173-6. doi: 10.1016/0014-5793(92)80761-5.
It has been shown that tandems of rare arginine codons AGG have a strong inhibitory effect on translation of mRNA in E. coli [5]. This has been explained by the rate-limiting interaction of these codons with the less abundant tRNA(AGG) [6]. In this study tandemly repeated AGG triplets were introduced into the chloramphenicol acetyltransferase (CAT) gene either upstream of the initiation ATG codon or downstream of it (both in frame and out of frame) and the expression of the modified genes was investigated. We report that the addition of AGG clusters resulted in a substantial inhibitory effect on CAT gene expression independently of their localization in mRNA. This inhibitory effect is explained by a competition of the tandem AGGAGG with the natural Shine-Dalgarno (SD) sequence (consensus AAGGAGGU) for the 3'-end of the 16S small ribosomal RNA (rRNA).
研究表明，稀有精氨酸密码子AGG的串联对大肠杆菌中mRNA的翻译具有强烈的抑制作用[5]。这是由于这些密码子与丰度较低的tRNA(AGG)之间的限速相互作用所致[6]。在本研究中，将串联重复的AGG三联体引入氯霉素乙酰转移酶（CAT）基因的起始ATG密码子上游或下游（包括框内和框外），并研究修饰基因的表达。我们报告，添加AGG簇对CAT基因表达产生了显著的抑制作用，而与它们在mRNA中的定位无关。这种抑制作用是由于串联的AGGAGG与天然的Shine-Dalgarno（SD）序列（共有序列AAGGAGGU）竞争16S小核糖体RNA（rRNA）的3'末端所致。
