Structure, molecular mechanism and biotechnological application of RNA thermometers

环境信号的直接感知直到最近才被认为是某些mRNA的固有特性。感觉RNA分子的5`-非翻译区（5`-UTR）中的构象变化被预测控制下游基因的转录或翻译。我们目前正在研究RNA温度计ROSE（热休克基因表达的抑制），它可能通过可逆的RNA折叠和解折叠来检测温度变化。根据我们的模型，翻译起始信号在低温下被掩蔽，而RNA结构在高温下的熔化通过允许核糖体进入Shine-Dalgarno区域来消除抑制。基于计算机的感觉RNA结构预测得到突变分析的支持，现在将通过各种技术进行测试，包括化学和酶探测实验。脚趾印分析将用于检查温度对核糖体与感觉RNA结合的影响。完成的微生物基因组序列将搜索其他RNA温度计，然后将通过一套互补的体内和体外技术进行研究。最后，RNA温度传感器将用于生物技术的目的，通过构建温度可控的表达载体。

Direct sensing of environmental cues has only recently been recognized as an intrinsic property of certain mRNAs. Conformational changes in the 5`-untranslated region (5`-UTR) of sensory RNA molecules are predicted to control either transcription or translation of downstream genes. We are currently studying the RNA thermometer ROSE (Repression Of heat Shock gene Expression) which presumably detects temperature changes via reversible RNA folding and unfolding. According to our model, translation initiation signals are masked at low temperatures, whereas melting of the RNA structure at elevated temperatures alleviates repression by allowing ribosome entry too the Shine-Dalgarno region. Computer-based structural predictions og the sensory RNA are supported by mutational analyses and will now be testet by various techniques, including chemical and enzymatic probing experiments. Toe-printing analyses will be used to examine the temperature effect on ribosome binding to the sensory RNA. Completed microbial genome sequences will be searched for other RNA thermometers which will then be studied by a complementary set of in vivo an in vitro techniques. Finally, RNA thermosensors will be exploited for biotechnological purposes by the construction of temperature-controllable expression vectors.