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A novel RNA polymerase‐binding protein that interacts with a sigma‐factor docking site
Author(s) -
Wang Erickson Anna F.,
Deighan Padraig,
Chen Shanshan,
Barrasso Kelsey,
Garcia Cinthia P.,
MartínezLumbreras Santiago,
Alfano Caterina,
Krysztofinska Ewelina M.,
Thapaliya Arjun,
Camp Amy H.,
Isaacson Rivka L.,
Hochschild Ann,
Losick Richard
Publication year - 2017
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.13724
Subject(s) - sigma factor , rna polymerase , biology , polymerase , rna polymerase ii , rna polymerase i , transcription (linguistics) , microbiology and biotechnology , rna dependent rna polymerase , specificity factor , rna , genetics , gene , promoter , gene expression , linguistics , philosophy
Summary Sporulation in Bacillus subtilis is governed by a cascade of alternative RNA polymerase sigma factors. We previously identified a small protein Fin that is produced under the control of the sporulation sigma factor σ F to create a negative feedback loop that inhibits σ F ‐directed gene transcription. Cells deleted for fin are defective for spore formation and exhibit increased levels of σ F ‐directed gene transcription. Based on pull‐down experiments, chemical crosslinking, bacterial two‐hybrid experiments and nuclear magnetic resonance chemical shift analysis, we now report that Fin binds to RNA polymerase and specifically to the coiled‐coil region of the β′ subunit. The coiled‐coil is a docking site for sigma factors on RNA polymerase, and evidence is presented that the binding of Fin and σ F to RNA polymerase is mutually exclusive. We propose that Fin functions by a mechanism distinct from that of classic sigma factor antagonists (anti‐ σ factors), which bind directly to a target sigma factor to prevent its association with RNA polymerase, and instead functions to inhibit σ F by competing for binding to the β′ coiled‐coil.