Zengel J M, Lindahl L
Department of Biology, University of Rochester, NY 14627.
Nucleic Acids Res. 1993 May 25;21(10):2429-35. doi: 10.1093/nar/21.10.2429.
Ribosomal protein L4 of Escherichia coli regulates expression of its own eleven gene S10 operon both by inhibiting translation and by stimulating premature termination of transcription. Both regulatory processes presumably involve L4 recognition of the S10 leader RNA. To help define L4's regulatory target, we have investigated the protein's cognate target on 23S rRNA. Binding of L4 to various fragments of the 23S rRNA was monitored by determining their ability to sequester L4 in an in vitro transcription system and thereby eliminate the protein's effect on transcription. Using this approach we identified a region of about 110 bases within domain I of 23S rRNA which binds L4. A two base deletion within this region, close to the base to which L4 has been cross-linked in intact 50S subunits, eliminates L4 binding. These results also confirm the prediction of the autogenous control model, that L4 bound to its target on rRNA is not active in regulating transcription of the S10 operon.
大肠杆菌的核糖体蛋白L4通过抑制翻译和刺激转录提前终止来调节其自身的11基因S10操纵子的表达。这两种调节过程可能都涉及L4对S10前导RNA的识别。为了帮助确定L4的调节靶点，我们研究了该蛋白在23S rRNA上的同源靶点。通过测定23S rRNA各个片段在体外转录系统中隔离L4的能力，从而消除该蛋白对转录的影响，来监测L4与23S rRNA不同片段的结合。使用这种方法，我们在23S rRNA的结构域I中确定了一个约110个碱基的区域，该区域与L4结合。该区域内靠近L4在完整50S亚基中发生交联的碱基处的两个碱基缺失，消除了L4的结合。这些结果也证实了自体控制模型的预测，即与rRNA上其靶点结合的L4在调节S10操纵子转录方面没有活性。
