Papers of the month

2013

• February 2013
  • For many essential genes of B. subtilis, it is not clear why they are essential in B. subtilis but not in closely related species. Strikingly, this is the case for RNases such as RNases III and Y. Now, Durand et al.. from the lab of Ciaran Condon have identified the reason for the essentiality of RNase III: This enzyme is required to degrade phage encoded toxin mRNA molecules thus protecting the cell from lysis caused by the encoded toxins. Indeed, RNase III is dispensable in a strain lacking the Skin element and the SPß prophage that harbor the corresponding toxin genes.
  • Relevant SubtiWiki pages: Ciaran Condon, RNase III, essential genes, yonT, txpA, toxins, antitoxins and immunity against toxins

Durand S, Gilet L, Condon C  
The essential function of B. subtilis RNase III is to silence foreign toxin genes. 
PLoS Genet. 2012 8(12): e1003181.
PubMed:23300471

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• January 2013
  • Castaing et al.. from the lab of Kumaran Ramamurthi show how ATP hydrolysis drives the self-association of SpoIVA into nucleotide-free filaments which then serve as a platform for the assembly of the spore coat starting with SpoVM. Together with the december's paper of the month these works demonstrate how ATP hydrolysis may contribute to different process wihtin a potein such as global conformational changes and self-assembly.
  • Relevant SubtiWiki pages: Kumaran Ramamurthi, SpoIVA, sporulation

2012

• December 2012
  • Kim et al.. show how the ATP hydrolysis controls the global conformation of the SecA translocase and drives protein secretion. The intricate network of structural interactions, which couple local electrostatic changes during ATP hydrolysis to global conformational and dynamic changes in SecA, form the foundation of the allosteric mechanochemistry that efficiently harnesses the chemical energy stored in ATP to drive complex mechanical processes.
  • Relevant SubtiWiki pages: SecA, protein secretion

• November 2012
  • Watson and Fedor identify the first ATP-responsive riboswitch. This riboswitch controls the expression of the ydaO gene and the ktrA-ktrB operon. Gene expression is decreased upon binding of ATP to the riboswitch. In consequence, the target genes are induced if the energy charge of the cell is low.
  • Relevant SubtiWiki pages: ydaO, ydaO riboswitch, riboswitch, ktrA-ktrB

• October 2012
  • Plata et al. from the labs of Dennis Vitkup and Uwe Sauer use a probabilistic approach to annotate genome-scale metabolic networks that integrates sequence homology and context-based correlations to functionally annotate so far unknown enzymes.
  • Relevant SubtiWiki pages: ykgB, spsI, spsJ, Uwe Sauer, Dennis Vitkup, metabolism

• September 2012
  • Chiba and Ito studied how the translation of YidC2, a membrane protein biogenesis factor, is controlled by SpoIIIJ availability via ribosome stalling of the mifM mRNA.
  • Relevant SubtiWiki pages: Koreaki Ito, translation, YidC2, SpoIIIJ, mifM

• August 2012
  • Houry et al. from the lab of Romain Briandet showed how motile Bacillus thuringiensis bacteria can penetrate a Staphylococcus aureus biofilm and eventually kill the biofilm bacteria with their antibacterial compounds.
  • Relevant SubtiWiki pages: Romain Briandet, Stephane Aymerich, biofilm formation, biosynthesis of antibacterial compounds

• July 2012
  • Dago et al. from the lab of Hendrik Szurmant studied the interactions between histidine kinase domains of two-component systems that result in autophosphorylation.
  • Relevant SubtiWiki pages: Hendrik Szurmant, Jim Hoch, two-component systems, KinA, KinD, protein-protein interactions

• June 2012
  • Kolodkin-Gal et al. from the labs of Roberto Kolter and Richard Losick demonstrate that D-amino acids produced by RacX and YlmE and norspermidine produced by GabT and YaaO act together in preventing biofilm formation and triggering biofilm disassembly.
  • Relevant SubtiWiki pages: Roberto Kolter, Richard Losick, biofilm formation, RacX, YlmE, GabT, YaaO

• May 2012
  • Elsholz et al. from the lab of Ulf Gerth demonstrate that protein phosphorylation on arginine residues is of great importance for B. subtilis. In addition to the previously identified target CtsR, 86 proteins are shown to be phosphorylated on arginine. The protein arginine kinase and phosphatase, McsB and YwlE, respectively, may thus have an important regulatory role in B. subtilis.
  • Relevant SubtiWiki pages: Ulf Gerth, Kürsad Turgay, Ulrike Mäder, Dörte Becher, Michael Hecker, phosphoproteins, protein kinases and phosphatases, McsB, YwlE

• April 2012
  • Meisner et al. and Levdikov et al. from the labs of Charles Moran and Tony Wilkinson, respectively, have reported the structure of the complex between SpoIIQ and SpoIIIAH. These two proteins interact through two membranes to connect the forespore and the mother cell during sporulation. The structure of the complex suggests that it is the extracellular component of a gap junction-like intercellular channel for the traffic of proteins between the two compartments.
  • Relevant SubtiWiki pages: Charles Moran, Tony Wilkinson, sporulation, SpoIIQ, SpoIIIAH

Levdikov VM, Blagova EV, McFeat A, Fogg MJ, Wilson KS, Wilkinson AJ  
Structure of components of an intercellular channel complex in sporulating Bacillus subtilis. 
Proc Natl Acad Sci U S A. 2012, 109(14):5441-5. 
PubMed:22431604

• March 2012
  • Buescher et al. and Nicolas et al. from the BaSysBio consortium diected by Philippe Noirot studied the dynamic metabolic and transcriptional responses of B. subtilis to changes of the growth conditions. One of the major issues is the adaptation of the cells upon a nutrient switch from glucose to malate and vice versa. Importantly, the study by Nicholas et al. provides an analysis of gene expression at 104 different conditions as revealed by tiling arrays.
  • Relevant SubtiWiki pages: Philippe Noirot, Michael Hecker, Uwe Völker, Philippe Bessières, Uwe Sauer, Stephane Aymerich, Tony Wilkinson, metabolism, transcription, CcpA, Sigma factors, sRNAs, Rho

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• February 2012
  • Levine et al. from the lab of Michael Elowitz show how B. subtilis cells can defer sporulation for multiple cell cycles in response to sudden environmental stress. This deferral is controlled by a pulsed positive feedback loop in which phosphorelay kinase expression is activated by pulses of Spo0A phosphorylation.
  • Relevant SubtiWiki pages: Michael Elowitz, Jonathan Dworkin, phosphorelay, sporulation, Spo0A

• A comment on this paper:

• January 2012
  • Segev et al. from the lab of Sigal Ben-Yehuda demonstrate that ribosomal RNAs are degraded in aging spores by RNase Y. Moreover, the authors show that individual mRNAs experience degradation or accumulation in spores. The study suggests that the kinetics of spore germination depends on the conditions that a spore had experienced before.
  • Relevant SubtiWiki pages: Sigal Ben-Yehuda, RNase Y, germination, RNases

2011

• December 2011
  • Bange et al. from the lab of Irmgard Sinning show how the FlhG protein activates the SRP-GTPase FlhF. The study sheds light on the evolutionary transition from RNA- to protein-driven activation in SRP-GTPases.
  • Relevant SubtiWiki pages: Irmgard Sinning, FlhF, FlhG, signal recognition particle, motility and chemotaxis

• November 2011
  • Locke et al. show how the SigB-dependent general stress response is controlled by signals using stochastic pulse frequency modulation through a compact regulatory architecture.
  • Relevant SubtiWiki pages: Michael Elowitz, SigB, General stress response

Locke JC, Young JW, Fontes M, Hernández Jiménez MJ, Elowitz MB  
Stochastic pulse regulation in bacterial stress response. 
Science. 2011 334:366-369. 
PubMed:21979936

• October 2011
  • Richards et al. identify the nudix hydrolase RppH as the pyrophosphohydrolase that triggers 5'-exonucleolytic degradation of mRNA by RNase J1 in B. subtilis.
  • Relevant SubtiWiki pages: David Bechhofer, Ciaran Condon, RNA processing and degradation, nudix hydrolase, RppH, RNase J1

• September 2011
  • A series of papers deals with RNA processing and degradation in B. subtilis. Three papers establish that RNase Y is the functional equivalent of RNase E from E. coli. Moreover, the role of RNase J1 in endonucleolytic cleavage of the trp leader mRNA is demonstrated.
  • Relevant SubtiWiki pages: David Bechhofer, Rick Lewis, Ulrike Mäder, Harald Putzer, Jörg Stülke, RNases, RNA degradosome, RNase Y, RNase Y targets, RNase J1

Lehnik-Habrink M, Schaffer M, Mäder U, Diethmaier C, Herzberg C, Stülke J  
RNA processing in Bacillus subtilis: identification of targets of the essential RNase Y. 
Mol Microbiol. 2011 81(6): 1459-73. 
PubMed:21815947

• August 2011
  • Chi et al. demonstrate that S-bacillithiolation of the repressor OhrR and of four enzymes of the methionine biosynthesis pathway protects the B. subtilis cell against hypochlorite stress.
  • Relevant SubtiWiki pages: Haike Antelmann, Dörte Becher, Ulrike Mäder, resistance against oxidative and electrophile stress, Spx regulon, CtsR regulon, PerR regulon, OhrR, MetE, YxjG, PpaC, SerA, YphP

• July 2011
  • Domínguez-Escobar et al. from Rut Carballido-Lopez' lab and Garner et al. report that movement of actin-like filaments is driven by the peptidoglycan elongation machinery. Both papers suggest that the MreB-like filaments serve to restrict the mobility of the peptidoglycan synthesizing machinery
    
  • Relevant SubtiWiki pages: Rut Carballido-Lopez, David Rudner, MreB, MreBH, Mbl, MreC, MreD, PbpA, RodA, RodZ, penicillin-binding proteins, cell shape, cell wall synthesis, cell wall biosynthetic complex

• A comment on these papers:

Andrew Jermy
Bacterial physiology: MreB takes a back seat.
Nat Rev Microbiol: 2011, 9(8);560-1
[PubMed:21725336] [WorldCat.org] [DOI] (I e)

• June 2011
  • Oppenheimer-Shaanan et al. from Sigal Ben-Yehuda's lab report that cyclic di-AMP acts as a secondary messenger that couples DNA integrity with progression of sporulation
    
  • Relevant SubtiWiki pages: Sigal Ben-Yehuda, DisA, GdpP, metabolism of signalling nucleotides, cell division

• May 2011
  • Miles et al. identified the enzyme for the key final step in the biosynthesis of queuosine, a hypermodified base found in the wobble positions of tRNA Asp, Asn, His, and Tyr from bacteria to man
    
  • Relevant SubtiWiki pages: QueG, translation