O'Connor M, Asai T, Squires C L, Dahlberg A E
J. W. Wilson Laboratory, Department of Molecular and Cellular Biology and Biochemistry, Brown University, Providence, RI 02912, USA. Michael_O'
Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):8973-8. doi: 10.1073/pnas.96.16.8973.
The downstream box (DB) is a sequence element that enhances translation of several bacterial and phage mRNAs. It has been proposed that the DB enhances translation by base pairing transiently to bases 1469-1483 of 16S rRNA, the so-called anti-DB, during the initiation phase of translation. We have tested this model of enhancer action by constructing mutations in the anti-DB that alter its mRNA base-pairing potential and examining expression of a variety of DB-containing mRNAs in strains expressing the mutant anti-DB 16S rRNA. We found that the rRNA mutant was viable and that expression of all tested DB-containing mRNAs was completely unaffected by radical alterations in the proposed anti-DB. These findings lead us to conclude that enhancement of translation by the DB does not involve mRNA-rRNA base pairing.
下游框（DB）是一种序列元件，可增强几种细菌和噬菌体mRNA的翻译。有人提出，在翻译起始阶段，DB通过与16S rRNA的1469 - 1483位碱基（即所谓的抗DB）短暂碱基配对来增强翻译。我们通过构建抗DB中的突变来改变其与mRNA的碱基配对潜力，并在表达突变抗DB 16S rRNA的菌株中检测多种含DB的mRNA的表达，以此来测试这种增强子作用模型。我们发现rRNA突变体是有活力的，并且所有测试的含DB的mRNA的表达完全不受所提出的抗DB的根本改变的影响。这些发现使我们得出结论，DB增强翻译并不涉及mRNA - rRNA碱基配对。
