Majdalani Nadim, Vanderpool Carin K, Gottesman Susan
Laboratory of Molecular Biology, National Cancer Institute, Bethesda, MD 20892, USA.
Crit Rev Biochem Mol Biol. 2005 Mar-Apr;40(2):93-113. doi: 10.1080/10409230590918702.
Small regulatory RNAs can modify the activity of proteins and the stability and translation of mRNAs. They have now been found in a wide range of organisms, and can play previously unsuspected critical regulatory roles. The bacterial small RNAs include two major classes. The largest family(with at least 20 members in Escherichia coli K12) acts by base pairing with target mRNAs to modify mRNA translation or stability; this class of RNAs also uses an RNA chaperone protein, Hfq. DsrA is the best-studied example of this family of RNAs. It has been shown to positively regulate translation of the transcription factor RpoS by opening an inhibitory hairpin in the mRNA, and to negatively regulate translation of hns by pairing just beyond the translation initiation codon. The class of RNAs that modify activity of proteins is exemplified by CsrB and CsrC of E. coli, two RNAs that bind to and inhibit CsrA, a protein translational regulator. Homologs of CsrA and related regulatory RNAs have been implicated in the regulation of gluconeogenesis, biofilm formation,and virulence factor expression in plant and human pathogens.
小调节RNA可以改变蛋白质的活性以及mRNA的稳定性和翻译过程。目前已在多种生物体中发现它们，并且它们可以发挥以前未被怀疑的关键调节作用。细菌小RNA包括两大类。最大的家族（在大肠杆菌K12中至少有20个成员）通过与靶mRNA碱基配对来改变mRNA的翻译或稳定性；这类RNA还利用一种RNA伴侣蛋白Hfq。DsrA是该RNA家族中研究最深入的例子。已表明它通过打开mRNA中的抑制性发夹结构来正向调节转录因子RpoS的翻译，并通过在翻译起始密码子之后配对来负向调节hns的翻译。修饰蛋白质活性的RNA类别的例子是大肠杆菌的CsrB和CsrC，这两种RNA与蛋白质翻译调节因子CsrA结合并抑制其活性。CsrA的同源物和相关的调节RNA已被证明参与植物和人类病原体中糖异生、生物膜形成和毒力因子表达的调节。
