Premium
FourU: a novel type of RNA thermometer in Salmonella
Author(s) -
Waldminghaus Torsten,
Heidrich Nadja,
Brantl Sabine,
Narberhaus Franz
Publication year - 2007
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2007.05794.x
Subject(s) - biology , salmonella , thermometer , rna , type (biology) , genetics , bacteria , ecology , physics , gene , quantum mechanics
Summary The translation of many heat shock and virulence genes is controlled by RNA thermometers. Usually, they are located in the 5′‐untranslated region (5′‐UTR) and block the Shine‐Dalgarno (SD) sequence by base pairing. Destabilization of the structure at elevated temperature permits ribosome binding and translation initiation. We have identified a new type of RNA thermometer in the 5′‐UTR of the Salmonella agsA gene, which codes for a small heat shock protein. Transcription of the agsA gene is controlled by the alternative sigma factor σ 32 . Additional translational control depends on a stretch of four uridines that pair with the SD sequence. Mutations in this region affect translation in vivo . Structure probing experiments demonstrate a temperature‐controlled opening of the SD region in vitro . Toeprinting (primer extension inhibition) shows that ribosome binding is dependent on high temperatures. Together with a postulated RNA thermometer upstream of the Yersinia pestis virulence gene lcrF ( virF ), the 5′‐UTR of Salmonella agsA might be the founding member of a new class of RNA thermometers that we propose to name ‘fourU’ thermometers.