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Genetic analysis of riboswitch-mediated transcriptional regulation responding to Mn2+ in Salmonella.
Shi, Yixin; Zhao, Guang; Kong, Wei.
Afiliación
  • Shi Y; Center for Infectious Diseases and Vaccinology, Biodesign Institute, and Arizona State University, Tempe, Arizona 85287-4501; School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501. Electronic address: yixin.shi@asu.edu.
  • Zhao G; Center for Infectious Diseases and Vaccinology, Biodesign Institute, and Arizona State University, Tempe, Arizona 85287-4501.
  • Kong W; Center for Infectious Diseases and Vaccinology, Biodesign Institute, and Arizona State University, Tempe, Arizona 85287-4501.
J Biol Chem ; 289(16): 11353-11366, 2014 Apr 18.
Article en En | MEDLINE | ID: mdl-24596096
Riboswitches are a class of cis-acting regulatory RNAs normally characterized from the 5'-UTR of bacterial transcripts that bind a specific ligand to regulate expression of associated genes by forming alternative conformations. Here, we present a riboswitch that contributes to transcriptional regulation through sensing Mn(2+) in Salmonella typhimurium. We characterized a 5'-UTR (UTR1) from the mntH locus encoding a Mn(2+) transporter, which forms a Rho-independent terminator to implement transcription termination with a high Mn(2+) selectivity both in vivo and in vitro. Nucleotide substitutions that cause disruption of the terminator interfere with the regulatory function of UTR1. RNA probing analyses outlined a specific UTR1 conformation that favors the terminator structure in Mn(2+)-replete condition. Switch sequence GCUAUG can alternatively base pair duplicated hexanucleotide CAUAGC to form either a pseudoknot or terminator stem. Mn(2+), but not Mg(2+), and Ca(2+), can enhance cleavage at specific nucleotides in UTR1. We conclude that UTR1 is a riboswitch that senses cytoplasmic Mn(2+) and therefore participates in Mn(2+)-responsive mntH regulation in Salmonella. This riboswitch domain is also conserved in several Gram-negative enteric bacteria, indicating that this Mn(2+)-responsive mechanism could have broader implications in bacterial gene expression. Additionally, a high level of cytoplasmic Mn(2+) can down-regulate transcription of the Salmonella Mg(2+) transporter mgtA locus in a Mg(2+) riboswitch-dependent manner. On the other hand, these two types of cation riboswitches do not share similarity at the primary or secondary structural levels. Taken together, characterization of Mn(2+)-responsive riboswitches should expand the scope of RNA regulatory elements in response to inorganic ions.
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Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Salmonella typhimurium / Proteínas Bacterianas / Regulación Bacteriana de la Expresión Génica / Proteínas de Transporte de Catión / Sitios Genéticos / Riboswitch / Manganeso Idioma: En Revista: J Biol Chem Año: 2014 Tipo del documento: Article

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Salmonella typhimurium / Proteínas Bacterianas / Regulación Bacteriana de la Expresión Génica / Proteínas de Transporte de Catión / Sitios Genéticos / Riboswitch / Manganeso Idioma: En Revista: J Biol Chem Año: 2014 Tipo del documento: Article