The orphan regulator ReiD of Salmonella enterica is essential for myo‐inositol utilization. Issue 3 (6th October 2014)

• Record Type: Journal Article
• Authors: Rothhardt, Johannes E.; Kröger, Carsten; Broadley, Steven P.; Fuchs, Thilo M.
• Is Part Of: Molecular microbiology. Volume 94:Issue 3(2014)
• Page Start: 700
• Page End: 712
• Publication Date: 2014-10-06
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12788
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>In <italic>S</italic><italic>almonella enterica</italic> serovar Typhimurium (<italic>S</italic>. Typhimurium), the genomic island GEI4417/4436 is responsible for the utilization of <italic>myo</italic>‐inositol (MI) as carbon and energy source. Here, we report the characterization of a novel, island‐encoded positive autoregulator termed ReiD (STM4423) that is specific to certain <italic>S</italic><italic>. enterica</italic> strains and <italic>E</italic><italic>scherichia coli</italic> strain ED1a able to use MI. ReiD was essential for growth with this polyol and also contributed to <italic>S</italic>. Typhimurium proliferation in swine caecum content. Providing higher copy numbers of ReiD reduced the long lag phase of 2 days during growth of <italic>S</italic>. Typhimurium in MI medium by 50%. In a heterologous host, expression of ReiD activated the transcription from the promoter of <italic>iolE</italic>/<italic>iolG</italic>, whose products catalyse the initial two steps in MI degradation. Episomal expression of <italic>iolE</italic>/<italic>iolG1</italic> rescued the otherwise zero growth phenotype of a <italic>reiD</italic> deletion mutant in MI medium. Gel mobility shift assays with purified ReiD demonstrated directed interaction of ReiD with its own promoter and that of <italic>iolE</italic>. The repressor IolR bound the <italic>reiD</italic> promoter, implying that <italic>reiD</italic> is part of the IolR regulon. Taken together, the regulator ReiD is a trigger to accelerate the switch from more easily accessible nutrients to MI utilization by <italic>S</italic>. Typhimurium.</p> </abstract>