茎环结构指导 3'UTR 衍生的小 RNA MicL 的精确加工。
Stem-loops direct precise processing of 3' UTR-derived small RNA MicL.
机构信息
Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892-5430, USA.
Department of Biochemistry, University of Cambridge, Tennis Court road, Cambridge CB2 1GA, UK.
出版信息
Nucleic Acids Res. 2019 Feb 20;47(3):1482-1492. doi: 10.1093/nar/gky1175.
Increasing numbers of 3'UTR-derived small, regulatory RNAs (sRNAs) are being discovered in bacteria, most generated by cleavage from longer transcripts. The enzyme required for these cleavages has been reported to be RNase E, the major endoribonuclease in enterica bacteria. Previous studies investigating RNase E have come to a range of different conclusions regarding the determinants for RNase E processing. To better understand the sequence and structure determinants for the precise processing of a 3' UTR-derived sRNA, we examined the cleavage of multiple mutant and chimeric derivatives of the 3' UTR-derived MicL sRNA in vivo and in vitro. Our results revealed that tandem stem-loops 3' to the cleavage site define optimal, correctly-positioned cleavage of MicL and probably other sRNAs. Moreover, our assays of MicL, ArcZ and CpxQ showed that sRNAs exhibit differential sensitivity to RNase E, likely a consequence of a hierarchy of sRNA features recognized by the endonuclease.
越来越多的 3'UTR 衍生的小调节 RNA（sRNA）在细菌中被发现，大多数由较长的转录物切割产生。报道称，这些切割所需的酶是 RNase E，它是肠杆菌中的主要内切核酸酶。以前的关于 RNase E 的研究对 RNase E 加工的决定因素得出了一系列不同的结论。为了更好地理解精确加工 3'UTR 衍生 sRNA 的序列和结构决定因素，我们在体内和体外研究了多个 MicL sRNA 的 3'UTR 衍生突变体和嵌合体衍生物的切割情况。我们的结果表明，切割位点 3'的串联茎环定义了 MicL 及可能其他 sRNA 的最佳、正确定位的切割。此外，我们对 MicL、ArcZ 和 CpxQ 的检测表明，sRNA 对 RNase E 的敏感性存在差异，这可能是内切核酸酶识别的 sRNA 特征的层次结构的结果。
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