期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：1
页码：184-188
DOI：10.1073/pnas.88.1.184
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The self-splicing rRNA intron of Tetrahymena thermophila belongs to a subgroup of group I introns that contain a conserved extra stem-loop structure termed P5abc. A Tetrahymena mutant precursor RNA lacking this P5abc is splicing-defective under standard conditions (5 mM MgCl2/200 mM NH4Cl, pH 7.5) in vitro. However, the mutant precursor RNA by itself is capable of performing the self-splicing reaction without P5abc under different conditions (15 mM MgCl2/2 mM spermidine, pH 7.5). We have investigated the functional role of the P5abc in the mechanism of the self-splicing reaction. When an RNA consisting of the P5abc but lacking the rest of the Tetrahymena intron is incubated with the mutant precursor, the self-splicing reaction proceeds highly efficiently under standard conditions (5 mM MgCl2/200 mM NH4Cl, pH 7.5). Two steps of the bimolecular self-splicing reaction can be performed accurately by a shortened precursor RNA containing all essential components required in the self-splicing reaction and an activator RNA consisting of the P5abc. Gel-mobility-shift assays suggest that two molecules associate by a direct RNA-RNA interaction during the splicing reaction. The results imply that there might exist other small RNAs whose role is to activate ribozymes.
