Your browser doesn't support javascript.
loading
A transient intermediate RNA structure underlies the regulatory function of the E. coli thiB TPP translational riboswitch.
Berman, Katherine E; Steans, Russell; Hertz, Laura M; Lucks, Julius B.
Afiliação
  • Berman KE; Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, Illinois 60208, USA.
  • Steans R; Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA.
  • Hertz LM; Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, Illinois 60208, USA.
  • Lucks JB; Department of Chemical and Biological Engineering, Northwestern University, Illinois 60208, USA jblucks@northwestern.edu.
RNA ; 29(11): 1658-1672, 2023 11.
Article em En | MEDLINE | ID: mdl-37419663
Riboswitches are cis-regulatory RNA elements that regulate gene expression in response to ligand binding through the coordinated action of a ligand-binding aptamer domain (AD) and a downstream expression platform (EP). Previous studies of transcriptional riboswitches have uncovered diverse examples that utilize structural intermediates that compete with the AD and EP folds to mediate the switching mechanism on the timescale of transcription. Here we investigate whether similar intermediates are important for riboswitches that control translation by studying the Escherichia coli thiB thiamin pyrophosphate (TPP) riboswitch. Using cellular gene expression assays, we first confirmed that the riboswitch acts at the level of translational regulation. Deletion mutagenesis showed the importance of the AD-EP linker sequence for riboswitch function. Sequence complementarity between the linker region and the AD P1 stem suggested the possibility of an intermediate nascent RNA structure called the antisequestering stem that could mediate the thiB switching mechanism. Experimentally informed secondary structure models of the thiB folding pathway generated from chemical probing of nascent thiB structures in stalled transcription elongation complexes confirmed the presence of the antisequestering stem, and showed it may form cotranscriptionally. Additional mutational analysis showed that mutations to the antisequestering stem break or bias thiB function according to whether the antisequestering stem or P1 is favored. This work provides an important example of intermediate structures that compete with AD and EP folds to implement riboswitch mechanisms.
Assuntos
Palavras-chave

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Riboswitch Idioma: En Revista: RNA Assunto da revista: BIOLOGIA MOLECULAR Ano de publicação: 2023 Tipo de documento: Article País de afiliação: Estados Unidos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Riboswitch Idioma: En Revista: RNA Assunto da revista: BIOLOGIA MOLECULAR Ano de publicação: 2023 Tipo de documento: Article País de afiliação: Estados Unidos