@article {1444,
	title = {Osmosensory signaling in Mycobacterium tuberculosis mediated by a eukaryotic-like Ser/Thr protein kinase.},
	journal = {Proc Natl Acad Sci U S A},
	volume = {110},
	year = {2013},
	month = {2013 Dec 24},
	pages = {E5069-77},
	abstract = {<p>Bacteria are able to adapt to dramatically different microenvironments, but in many organisms, the signaling pathways, transcriptional programs, and downstream physiological changes involved in adaptation are not well-understood. Here, we discovered that osmotic stress stimulates a signaling network in Mycobacterium tuberculosis regulated by the eukaryotic-like receptor Ser/Thr protein kinase PknD. Expression of the PknD substrate Rv0516c was highly induced by osmotic stress. Furthermore, Rv0516c disruption modified peptidoglycan thickness, enhanced antibiotic resistance, and activated genes in the regulon of the alternative σ-factor SigF. Phosphorylation of Rv0516c regulated the abundance of EspA, a virulence-associated substrate of the type VII ESX-1 secretion system. These findings identify an osmosensory pathway orchestrated by PknD, Rv0516c, and SigF that enables adaptation to osmotic stress through cell wall remodeling and virulence factor production. Given the widespread occurrence of eukaryotic-like Ser/Thr protein kinases in bacteria, these proteins may play a broad role in bacterial osmosensing.</p>},
	keywords = {Adaptation, Biological, Blotting, Western, Gene Expression Regulation, Bacterial, Green Fluorescent Proteins, Microarray Analysis, Mycobacterium tuberculosis, Osmolar Concentration, Osmotic Pressure, Phosphorylation, Protein Kinases, Signal Transduction},
	issn = {1091-6490},
	doi = {10.1073/pnas.1321205110},
	author = {Hatzios, Stavroula K and Baer, Christina E and Rustad, Tige R and Siegrist, M Sloan and Pang, Jennifer M and Ortega, Corrie and Alber, Tom and Grundner, Christoph and Sherman, David R and Bertozzi, Carolyn R}
}
@article {394,
	title = {Inducible protein degradation in Bacillus subtilis using heterologous peptide tags and adaptor proteins to target substrates to the protease ClpXP.},
	journal = {Mol Microbiol},
	volume = {70},
	year = {2008},
	month = {2008 Nov},
	pages = {1012-25},
	abstract = {The ability to manipulate protein levels is useful for dissecting regulatory pathways, elucidating gene function and constructing synthetic biological circuits. We engineered an inducible protein degradation system for use in Bacillus subtilis based on Escherichia coli and Caulobacter crescentusssrA tags and SspB adaptors that deliver proteins to ClpXP for proteolysis. In this system, modified ssrA degradation tags are fused onto the 3{\textquoteright} end of the genes of interest. Unlike wild-type ssrA, these modified tags require the adaptor protein SspB to target tagged proteins for proteolysis. In the absence of SspB, the tagged proteins accumulate to near physiological levels. By inducing SspB expression from a regulated promoter, the tagged substrates are rapidly delivered to the B. subtilis ClpXP protease for degradation. We used this system to degrade the reporter GFP and several native B. subtilis proteins, including, the transcription factor ComA, two sporulation kinases (KinA, KinB) and the sporulation and chromosome partitioning protein Spo0J. We also used modified E. coli and C. crescentus ssrA tags to independently control the degradation of two different proteins in the same cell. These tools will be useful for studying biological processes in B. subtilis and can potentially be modified for use in other bacteria.},
	keywords = {Alleles, Bacillus subtilis, Bacterial Proteins, Carrier Proteins, Caulobacter crescentus, DNA-Binding Proteins, Endopeptidase Clp, Escherichia coli, Escherichia coli Proteins, Gene Expression Regulation, Bacterial, Genetic Vectors, Green Fluorescent Proteins, Plasmids, Promoter Regions, Genetic, Protein Engineering, RNA, Bacterial, Substrate Specificity},
	issn = {1365-2958},
	doi = {10.1111/j.1365-2958.2008.06467.x},
	author = {Griffith, Kevin L and Grossman, Alan D}
}
@article {814,
	title = {XthA (Exonuclease III) regulates loading of RecA onto DNA substrates in log phase Escherichia coli cells.},
	journal = {Mol Microbiol},
	volume = {67},
	year = {2008},
	month = {2008 Jan},
	pages = {88-101},
	abstract = {Exonucleases can modify DNA substrates created during DNA replication, recombination and repair. In Escherichia coli, the effects of several 3{\textquoteright}-5{\textquoteright} exonucleases on RecA loading were studied by assaying RecA-GFP foci formation. Mutations in xthA (ExoIII), xseAB (ExoVII), xni (ExoIX), exoX (ExoX) and tatD (ExoXI) increased the number of RecA-GFP foci twofold to threefold in a population of log phase cells grown in minimal medium. These increases depend on xonA. Epistasis analysis shows that ExoVII, ExoX, ExoIX and ExoXI function in a common pathway, distinct from ExoIII (and ExoI is upstream of both pathways). It is shown (paradoxically) that in xthA mutants, RecA-GFP loading is predominantly RecBCD-dependent and that xthA recB double mutants are viable. Experiments show that while log phase xthA cells have twofold more double-stranded breaks (DSBs) than wild type, they do not induce the SOS response. The increase in RecA loading is independent of the base excision repair (BER) proteins Nth, MutM and Nei. It is proposed that log phase cells produce DSBs that do not induce the SOS response. Furthermore, ExoI, ExoIII and the other 3{\textquoteright}-5{\textquoteright} exonucleases process these DSBs, antagonizing the RecBCD pathway of RecA loading, thus regulating the availability of these substrates for recombination.},
	keywords = {DNA Breaks, Double-Stranded, DNA Repair, DNA, Bacterial, Epistasis, Genetic, Escherichia coli K12, Escherichia coli Proteins, Exodeoxyribonucleases, Green Fluorescent Proteins, Microbial Viability, Rec A Recombinases, Recombinant Fusion Proteins, SOS Response (Genetics)},
	issn = {0950-382X},
	doi = {10.1111/j.1365-2958.2007.06026.x},
	author = {Centore, Richard C and Lestini, Roxane and Sandler, Steven J}
}
@article {817,
	title = {UvrD limits the number and intensities of RecA-green fluorescent protein structures in Escherichia coli K-12.},
	journal = {J Bacteriol},
	volume = {189},
	year = {2007},
	month = {2007 Apr},
	pages = {2915-20},
	abstract = {RecA is important for recombination, DNA repair, and SOS induction. In Escherichia coli, RecBCD, RecFOR, and RecJQ prepare DNA substrates onto which RecA binds. UvrD is a 3{\textquoteright}-to-5{\textquoteright} helicase that participates in methyl-directed mismatch repair and nucleotide excision repair. uvrD deletion mutants are sensitive to UV irradiation, hypermutable, and hyper-rec. In vitro, UvrD can dissociate RecA from single-stranded DNA. Other experiments suggest that UvrD removes RecA from DNA where it promotes unproductive reactions. To test if UvrD limits the number and/or the size of RecA-DNA structures in vivo, an uvrD mutation was combined with recA-gfp. This recA allele allows the number of RecA structures and the amount of RecA at these structures to be assayed in living cells. uvrD mutants show a threefold increase in the number of RecA-GFP foci, and these foci are, on average, nearly twofold higher in relative intensity. The increased number of RecA-green fluorescent protein foci in the uvrD mutant is dependent on recF, recO, recR, recJ, and recQ. The increase in average relative intensity is dependent on recO and recQ. These data support an in vivo role for UvrD in removing RecA from the DNA.},
	keywords = {DNA Helicases, DNA, Bacterial, DNA-Binding Proteins, Escherichia coli K12, Escherichia coli Proteins, Green Fluorescent Proteins, Molecular Sequence Data, Mutagenesis, Rec A Recombinases, Recombinant Fusion Proteins},
	issn = {0021-9193},
	doi = {10.1128/JB.01777-06},
	author = {Centore, Richard C and Sandler, Steven J}
}
@article {820,
	title = {Localization of RecA in Escherichia coli K-12 using RecA-GFP.},
	journal = {Mol Microbiol},
	volume = {57},
	year = {2005},
	month = {2005 Aug},
	pages = {1074-85},
	abstract = {RecA is important in recombination, DNA repair and repair of replication forks. It functions through the production of a protein-DNA filament. To study the localization of RecA in live Escherichia coli cells, the RecA protein was fused to the green fluorescence protein (GFP). Strains with this gene have recombination/DNA repair activities three- to tenfold below wild type (or about 1000-fold above that of a recA null mutant). RecA-GFP cells have a background of green fluorescence punctuated with up to five foci per cell. Two types of foci have been defined: 4,6-diamidino-2-phenylindole (DAPI)-sensitive foci that are bound to DNA and DAPI-insensitive foci that are DNA-less aggregates/storage structures. In log phase cells, foci were not localized to any particular region. After UV irradiation, the number of foci increased and they localized to the cell centre. This suggested colocalization with the DNA replication factory. recA, recB and recF strains showed phenotypes and distributions of foci consistent with the predicted effects of these mutations.},
	keywords = {Chromosomes, Bacterial, DNA Replication, DNA, Bacterial, Escherichia coli, Escherichia coli Proteins, Green Fluorescent Proteins, Mutation, Rec A Recombinases, Recombinant Fusion Proteins, Recombination, Genetic, Ultraviolet Rays},
	issn = {0950-382X},
	doi = {10.1111/j.1365-2958.2005.04755.x},
	author = {Renzette, Nicholas and Gumlaw, Nathan and Nordman, Jared T and Krieger, Marlee and Yeh, Su-Ping and Long, Edward and Centore, Richard and Boonsombat, Ruethairat and Sandler, Steven J}
}
