Forster A C, Altman S
Department of Biology, Yale University, New Haven, CT 06520.
Science. 1990 Aug 17;249(4970):783-6. doi: 10.1126/science.1697102.
Ribonuclease P (RNase P) from Escherichia coli or its catalytic RNA subunit can efficiently cleave small RNA substrates that lack the conserved features of natural substrates of RNase P if an additional small RNA is also present. This additional RNA must contain a sequence complementary to the substrate [external guide sequence (EGS)] and a 3'-proximal CCA sequence to ensure cleavage. The aminoacyl acceptor stem and some additional 5'- and 3'-terminal sequences of a precursor transfer RNA are sufficient to allow efficient cleavage by RNAase P, and the 2'-hydroxyl group at the cleavage site is not absolutely necessary for cleavage. In principle, any RNA could be targeted by a custom-designed EGS RNA for specific cleavage by RNase P in vitro or in vivo.
来自大肠杆菌的核糖核酸酶P（RNase P）或其催化性RNA亚基，如果同时存在另一种小RNA，就能高效切割缺乏RNase P天然底物保守特征的小RNA底物。这种额外的RNA必须包含与底物互补的序列[外部引导序列（EGS）]和一个3'近端CCA序列以确保切割。前体转运RNA的氨酰受体茎以及一些额外的5'和3'末端序列足以使RNase P进行高效切割，并且切割位点处的2'-羟基对于切割并非绝对必需。原则上，任何RNA都可以被定制设计的EGS RNA靶向，以便在体外或体内被RNase P进行特异性切割。
