Identification in a pseudoknot of a U⋅G motif essential for the regulation of the expression of ribosomal protein S15
Abstract
The ribosomal protein S15 from Escherichia coli binds to a pseudoknot in its own messenger. This interaction is an essential step in the mechanism of S15 translational autoregulation. In a previous study, a recognition determinant for S15 autoregulation, involving a U⋅G wobble pair, was located in the center of stem I of the pseudoknot. In this study, an extensive mutagenesis analysis has been conducted in and around this U⋅G pair by comparing the effects of these mutations on the expression level of S15. The results show that the U⋅G wobble pair cannot be substituted by A⋅G, C⋅A, A⋅C, G⋅U, or C⋅G without loss of the autocontrol. In addition, the base pair C⋅G, adjacent to the 5' side of U, cannot be flipped or changed to another complementary base pair without also inducing derepression of translation. A unique motif, made of only two adjacent base pairs, U⋅G/C⋅G, is essential for S15 autoregulation and is presumably involved in direct recognition by the S15 protein.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- March 1998
- DOI:
- 10.1073/pnas.95.5.2564
- Bibcode:
- 1998PNAS...95.2564B