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An evolutionarily conserved RNase ‐based mechanism for repression of transcriptional positive autoregulation
Author(s) -
Wurtmann Elisabeth J.,
Ratushny Alexander V.,
Pan Min,
Beer Karlyn D.,
Aitchison John D.,
Baliga Nitin S.
Publication year - 2014
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/mmi.12564
Subject(s) - biology , psychological repression , transcriptional regulation , gene , genetics , rnase p , operon , microbiology and biotechnology , computational biology , transcription factor , rna , gene expression , mutant
Summary It is known that environmental context influences the degree of regulation at the transcriptional and post‐transcriptional levels. However, the principles governing the differential usage and interplay of regulation at these two levels are not clear. Here, we show that the integration of transcriptional and post‐transcriptional regulatory mechanisms in a characteristic network motif drives efficient environment‐dependent state transitions. Through phenotypic screening, systems analysis, and rigorous experimental validation, we discovered an RNase ( VNG2099C ) in H alobacterium salinarum that is transcriptionally co‐regulated with genes of the aerobic physiologic state but acts on transcripts of the anaerobic state. Through modelling and experimentation we show that this arrangement generates an efficient state‐transition switch, within which R Nase ‐repression of a transcriptional p ositive a uto r egulation ( RPAR ) loop is critical for shutting down ATP ‐consuming active potassium uptake to conserve energy required for salinity adaptation under aerobic, high potassium, or dark conditions. Subsequently, we discovered that many E scherichia coli operons with energy‐associated functions are also putatively controlled by RPAR indicating that this network motif may have evolved independently in phylogenetically distant organisms. Thus, our data suggest that interplay of transcriptional and post‐transcriptional regulation in the RPAR motif is a generalized principle for efficient environment‐dependent state transitions across prokaryotes.