Been M D, Cech T R
Cell. 1986 Oct 24;47(2):207-16. doi: 10.1016/0092-8674(86)90443-5.
The specificity of reactions catalyzed by the Tetrahymena pre-rRNA intervening sequence (IVS) was studied using site-specific mutagenesis. Two sequences required for 5' splice-site selection during self-splicing were defined. Single-base changes in either a 5' exon sequence or a 5' exon-binding site within the IVS disrupt their ability to pair and result in inefficient or inaccurate splicing. Combinations that restore complementarity suppress the effect of the single-base changes. Sequence alterations in the 5' exon-binding site also change the specificity of two other reactions: intermolecular exon ligation (trans-splicing) and the enzymatic nucleotidyltransferase activity of the IVS RNA. Thus the substrate specificity of an RNA enzyme can be changed in a manner predictable by the rules of Watson-Crick base-pairing.
利用位点特异性诱变研究了嗜热四膜虫前体rRNA间隔序列（IVS）催化反应的特异性。定义了自我剪接过程中5'剪接位点选择所需的两个序列。IVS内5'外显子序列或5'外显子结合位点的单碱基变化会破坏它们配对的能力，并导致剪接效率低下或不准确。恢复互补性的组合可抑制单碱基变化的影响。5'外显子结合位点的序列改变也会改变另外两个反应的特异性：分子间外显子连接（反式剪接）和IVS RNA的酶促核苷酸转移酶活性。因此，RNA酶的底物特异性可以按照沃森-克里克碱基配对规则预测的方式改变。
