ALTERNATIVE MESSENGER-RNA STRUCTURES OF THE CIII-GENE OF BACTERIOPHAGE-LAMBDA DETERMINE THE RATE OF ITS TRANSLATION INITIATION
ALTERNATIVE MESSENGER-RNA STRUCTURES OF THE CIII-GENE OF BACTERIOPHAGE-LAMBDA DETERMINE THE RATE OF ITS TRANSLATION INITIATION
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DOI：
10.1016/0022-2836(89)90329-x
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发表时间：
1989-11-20
影响因子：
5.6
通讯作者：
OPPENHEIM, AB
中科院分区：
文献类型：
--
作者：
ALTUVIA, S;KORNITZER, D;OPPENHEIM, AB
噬菌体。cIII基因产物在感染后的溶解菌-溶原性决定中具有调节功能。一组cIII表达突变体的可用性使我们能够建立cIII mRNA的结构-功能关系。我们证明，使用定义的体外系统，cIII mRNA在平衡状态下存在两种构象。已经证明导致cIII过表达的突变被发现在一个确认（结构B）中冻结RNA，并允许有效地与30s核糖体亚基结合。已经证明阻止cIII翻译的突变会导致mRNA呈现另一种构象（结构A）。在这种结构中，翻译起始区被阻断，从而阻止30s核糖体亚基结合。通过改变温度或Mg2+浓度，可以改变野生型mRNA中替代结构的相对比例。我们认为，两种mRNA构象之间的平衡调节为控制cIII基因的表达提供了一种机制。
The bacteriophage .lambda. cIII gene product has a regulatory function in the lysis-lysogeny decision following infection. The availability of a set of cIII expression mutants allowed us to establish the structure-function relationship of the cIII mRNA. We demonstrate, using defined in vitro systems, that the cIII mRNA is present in two conformations at equilibrium. Mutations that have been shown to lead to cIII overexpression were found to freeze the RNA in one confirmation (structure B), and permit efficient binding to the 30 S ribosomal subunit. Mutations that have been shown to prevent cIII translation cause the mRNA to assume the alternative conformation (structure A). In this structure, the translation initiation region is occluded, thereby preventing 30 S ribosomal subunit binding. By varying the temperature or Mg2+ concentration it was possible to alter the relative proportion of the alternative structures in wild-type mRNA. We suggest that the regulation of the equilibrium between the two mRNA conformations provides a mechanism for the control of cIII gene expression.