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3 Publications visible to you, out of a total of 3

Abstract (Expand)

Bacteria adapt to environmental stimuli by adjusting their transcriptomes in a complex manner, the full potential of which has yet to be established for any individual bacterial species. Here, we report the transcriptomes of Bacillus subtilis exposed to a wide range of environmental and nutritional conditions that the organism might encounter in nature. We comprehensively mapped transcription units (TUs) and grouped 2935 promoters into regulons controlled by various RNA polymerase sigma factors, accounting for ~66% of the observed variance in transcriptional activity. This global classification of promoters and detailed description of TUs revealed that a large proportion of the detected antisense RNAs arose from potentially spurious transcription initiation by alternative sigma factors and from imperfect control of transcription termination.

Authors: Pierre Nicolas, , Etienne Dervyn, Tatiana Rochat, Aurélie Leduc, Nathalie Pigeonneau, Elena Bidnenko, Elodie Marchadier, Mark Hoebeke, Stéphane Aymerich, Dörte Becher, Paola Bisicchia, Eric Botella, Olivier Delumeau, Geoff Doherty, Emma L Denham, Mark J Fogg, Vincent Fromion, Anne Goelzer, Annette Hansen, Elisabeth Härtig, , Georg Homuth, Hanne Jarmer, Matthieu Jules, Edda Klipp, Ludovic Le Chat, François Lecointe, , Wolfram Liebermeister, Anika March, , , David Noone, Susanne Pohl, Bernd Rinn, Frank Rügheimer, , Franck Samson, Marc Schaffer, Benno Schwikowski, , , Thomas Wiegert, Kevin M Devine, Anthony J Wilkinson, , , , Philippe Bessières, Philippe Noirot

Date Published: 3rd Mar 2012

Publication Type: Not specified

Abstract (Expand)

The RNA degradosome is a multiprotein macromolecular complex that is involved in the degradation of messenger RNA in bacteria. The composition of this complex has been found to display a high degree of evolutionary divergence, which may reflect the adaptation of species to different environments. Recently, a degradosome-like complex identified in Bacillus subtilis was found to be distinct from those found in proteobacteria, the degradosomes of which are assembled around the unstructured C-terminus of ribonuclease E, a protein not present in B. subtilis. In this report, we have investigated in vitro the binary interactions between degradosome components and have characterized interactions between glycolytic enzymes, RNA-degrading enzymes, and those that appear to link these two cellular processes. The crystal structures of the glycolytic enzymes phosphofructokinase and enolase are presented and discussed in relation to their roles in the mediation of complex protein assemblies. Taken together, these data provide valuable insights into the structure and dynamics of the RNA degradosome, a fascinating and complex macromolecular assembly that links RNA degradation with central carbon metabolism.

Authors: , Lorraine Hewitt, Cecilia Rodrigues, Alexandra S Solovyova, ,

Date Published: 16th Dec 2011

Publication Type: Not specified

Abstract (Expand)

Twin-arginine protein translocation (Tat) pathways are required for transport of folded proteins across bacterial, archaeal and chloroplast membranes. Recent studies indicate that Tat has evolved into a mainstream pathway for protein secretion in certain halophilic archaea, which thrive in highly saline environments. Here, we investigated the effects of environmental salinity on Tat-dependent protein secretion by the Gram-positive soil bacterium Bacillus subtilis, which encounters widely differing salt concentrations in its natural habitats. The results show that environmental salinity determines the specificity and need for Tat-dependent secretion of the Dyp-type peroxidase YwbN in B. subtilis. Under high salinity growth conditions, at least three Tat translocase subunits, namely TatAd, TatAy and TatCy, are involved in the secretion of YwbN. Yet, a significant level of Tat-independent YwbN secretion is also observed under these conditions. When B. subtilis is grown in medium with 1% NaCl or without NaCl, the secretion of YwbN depends strictly on the previously described "minimal Tat translocase" consisting of the TatAy and TatCy subunits. Notably, in medium without NaCl, both tatAyCy and ywbN mutants display significantly reduced exponential growth rates and severe cell lysis. This is due to a critical role of secreted YwbN in the acquisition of iron under these conditions. Taken together, our findings show that environmental conditions, such as salinity, can determine the specificity and need for the secretion of a bacterial Tat substrate.

Authors: René van der Ploeg, , Georg Homuth, Marc Schaffer, Emma L Denham, Carmine G Monteferrante, Marcus Miethke, Mohamed A Marahiel, , Theresa Winter, , Haike Antelmann,

Date Published: 30th Mar 2011

Publication Type: Not specified

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