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  • 1
    Electronic Resource
    Electronic Resource
    Multiple histidine kinases regulate entry into stationary phase and sporulation in Bacillus subtilis (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 38 (2000), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Protein homology studies identified five kinases potentially capable of phosphorylating the Spo0F response regulator and initiating sporulation in Bacillus subtilis. Two of these kinases, KinA and KinB, were known from previous studies to be responsible for sporulation in laboratory media. In vivo studies of the activity of four of the kinases, KinA, KinC, KinD (ykvD) and KinE (ykrQ), using abrB transcription as an indicator of Spo0A∼P level, revealed that KinC and KinD were responsible for Spo0A∼P production during the exponential phase of growth in the absence of KinA and KinB. In vitro, all four kinases dephosphorylated Spo0F∼P with the production of ATP at approximately the same rate, indicating that they possess approximately equal affinity for Spo0F. All the kinases were expressed during growth and early stationary phase, suggesting that the differential activity observed in growth and sporulation results from differential activation by signal ligands unique to each kinase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.2000.02148.x
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  • 2
    Electronic Resource
    Electronic Resource
    Alanine mutants of the Spo0F response regulator modifying specificity for sensor kinases in sporulation initiation (1999)
    Oxford BSL : Blackwell Science Ltd
    Molecular microbiology 33 (1999), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Five single alanine substitution mutations in the Spo0F response regulator gave rise to mutant strains of Bacillus subtilis with seemingly normal sporulation that nevertheless rapidly segregated variants blocked in sporulation. The basis for this deregulated phenotype was postulated to be increased phosphorylation of the Spo0A transcription factor, resulting from enhanced phosphate input or decreased dephosphorylation of the phosphorelay. Strains bearing two of these Spo0F mutant proteins, Y13A and I17A, retained a requirement for KinA and KinB kinases in sporulation, whereas the remaining three, L66A, I90A and H101A, gave strains that sporulated well in the absence of both KinA and KinB. Sporulation of strains bearing L66A and H101A mutations was decreased in a mutant lacking KinA, KinB and KinC, but the strain bearing the I90A mutation required the further deletion of KinD to lower its sporulation frequency. The affected residues, L-66, I-90 and H-101, are involved in crucial hydrophobic contacts stabilizing the orientation of helix α4 of Spo0F. The data are consistent with the notion that these three mutations alter the conformation of the β4–α4 loop of Spo0F that is known to contain residues critical for KinA:Spo0F recognition. As this loop has a propensity for multiple conformations, the spatial arrangement of this loop may play a critical role in kinase selection by Spo0F and might be altered by regulatory molecules interacting with Spo0F.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1999.01481.x
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  • 3
    Electronic Resource
    Electronic Resource
    A negative regulator linking chromosome segregation to developmental transcription in Bacillus subtilis (1998)
    Oxford BSL : Blackwell Science Ltd, UK
    Molecular microbiology 29 (1998), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The Spo0JA and Spo0JB proteins of Bacillus subtilis are similar to the ParA and ParB plasmid-partitioning proteins, respectively, and mutation of spo0JB prevents the expression of stage II genes of sporulation. This phenotype is a consequence of Spo0JA activity in the absence of Spo0JB, and its basis was unknown. In the studies reported here, Spo0JA was found specifically to dissociate transcription initiation complexes formed in vitro by the phosphorylated sporulation transcription factor Spo0A and RNA polymerase with the spoIIG promoter. This repressor-like activity is likely to be the basis for preventing the onset of differentiation in vivo. Spo0JB is known to neutralize Spo0JA activity in vivo and also to interact with a mitotic-like apparatus responsible for chromosome partitioning. These data suggest that Spo0JA and Spo0JB form a regulatory link between chromosome partition and development gene expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1998.00905.x
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  • 4
    Electronic Resource
    Electronic Resource
    Alterations in the flow of one-carbon units affect KinB-dependent sporulation in Bacillus subtilis (1997)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 25 (1997), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Endospore formation in Bacillus subtilis is primarily dependent on the phosphorylation of the key transcription factor Spo0A by two major kinases, KinA and KinB, thought to be activated by distinct signals. Using a strategy designed to detect mutations that specifically affect the signalling pathway to KinB, we have isolated a Tn10 insertion mutant in one of two adjacent lrp-like genes coding for homologues of the Escherichia coli leucine-responsive regulatory protein (Lrp) and another mutant in the glyA gene encoding the serine hydroxymethyl transferase (SHMT). SHMT catalyses interconversion of serine and glycine while transferring the resulting one-carbon unit into the C1 pool through methylene tetrahydrofolate. Sporulation experiments performed in a series of supplemented media indicated that the role of SHMT in the KinB pathway is to feed the pool of C1 units recruited for the biosynthesis of key metabolites, which include the methyl donor S-adenosyl-methionine (SAM). The results of experiments using l-ethionine suggest that SAM is involved in post-synthetic methylation reactions or biosynthesis of metabolites that serve to activate KinB. Truncated LrpA and LrpB peptides that have retained the DNA-binding domain but have lost the C-terminal half of the protein appear to act as repressors of glyA transcription and KinB-dependent sporulation. However, deletions of lrpA, lrpB or lrpAB have little effect on glyA transcription or sporulation through KinB, suggesting that other effectors, such as additional Lrp homologues, may act in conjunction with LrpA and LrpB. Our results indicate that lrpA–lrpB together with the biosynthetic glyA gene lie on a common signalling pathway meant to activate the KinB sensor kinase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1997.4491805.x
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  • 5
    Electronic Resource
    Electronic Resource
    Transition-state regulators: sentinels of Bacillus subtilis post-exponential gene expression (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 7 (1993), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: When Bacillus subtilis encounters a nutrient-depleted environment, it expresses a wide variety of genes that encode functions in alternative pathways of metabolism and energy production. Expression of these genes first occurs during the transition from active growth into stationary phase and is controlled by a class of proteins termed transition-state regulators. In several instances, a given gene is redundantly controlled by two or more of these regulators and many of these regulators control genes in numerous different pathways. The AbrB, Hpr and Sin proteins are the best-studied examples of these regulatory molecules. Their role is to prevent inappropriate and possibly detrimental functions from being expressed during exponential growth when they are not needed. They serve as elements integrating sporulation with ancillary stationary-phase phenomena and appear to participate in the timing of early sporulation events and in fine-tuning the magnitude of gene expression in response to specific environmental conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.1993.tb01125.x
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  • 6
    Electronic Resource
    Electronic Resource
    Multisensory activation of the phosphorelay initiating sporulation in Bacillus subtilis: identification and sequence of the protein kinase of the alternate pathway (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 8 (1993), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The phosphorelay is the signal-transduction system recognizing and integrating environmental signals to initiate sporulation. The major signal input to the phosphorelay is an ATP-dependent kinase, KinA, responsible for phosphorylating the Spo0F protein. Mutants lacking KinA, however, still sporulate, suggesting that other kinases can fulfil its role. In order to identify these kinases, genes for kinases were isolated by hybridization using a degenerate oligonucleotide probe designed for common regions of this class of kinases. A gene for a second kinase, KinB, was isolated which gave a sporulation negative phenotype when inactivated in a kinA background. The kinB locus was sequenced and found to be a small operon consisting of the kinB gene and another gene, kapB, transcribed from a single σ;A-dependent promoter. Inactivation of either kinB or kapB in a kinA strain led to severe sporulation deficiency. The kinB gene coded for a 47774 Mr protein with the carboxyl half of this protein highly homologous to the same domain of KinA. The amino-terminal domain of KinB was hydro-phobic with six recognizable membrane-spanning regions. The kapB gene coded for a moderately charged, probably soluble, protein of 14666 Mr, with no homology to any known protein. Genetic evidence suggests that KapB is required either for the function of KinB or for its expression. Although double mutants kinA kinB cannot sporulate and assume a stage 0 phenotype, the SpoA∼P-dependent regulation of the abrB gene is normal in these strains, suggesting that low levels of SpoA∼P accumulate even in the absence of both kinases. This accumulation is dependent on functional spoOF and spoOB genes and its source is unknown. The KinA and KinB pathways are the only pathways capable of producing sufficient SpoOA∼P to allow initiation and completion of sporulation under laboratory conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.1993.tb01204.x
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  • 7
    Electronic Resource
    Electronic Resource
    A positive feedback loop controls transcription of the spo0F gene, a component of the sporulation phosphorelay In Bacillus subtilis (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 7 (1993), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The spo0Fgene of Bacillus subtilisencodes a protein that functions as a secondary messenger in a phosphorelay system controlling the initiation of sporulation. Transcription of the spo0F gene was known to be dependent on an intact gene for the transcription regulator Spo0A. In vitro footprint analysis revealed that Spo0A protein bound to two locations in the spo0F promoter region. Deletion of a 40 bp region upstream of one of the promoters (P2) abolished the activation of spo0Fexpression that occurs at the onset of stationary phase and sporulation. This 40 bp region contains a Spo0A-binding site. These observations are consistent with a hypothesis that Spo0A binding to this region is responsible for activating spo0F transcription. Additionally, Spo0A binding at a downstream site could modulate the level of this activation. Since Spo0F protein is required for the formation of Spo0A∼P (the form needed for transcriptional activation) a positive feedback loop controls transcription of spo0F.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.1993.tb01188.x
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  • 8
    Electronic Resource
    Electronic Resource
    Aspartyl-phosphate phosphatases deactivate the response regulator components of the sporulation signal transduction system in Bacillus subtilis (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 19 (1996), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Bacteria use two-component signal transduction systems to sense and respond to their environment. A sensor kinase and a response-regulator transcription factor work in concert by phosphorylation/dephosphorylation through kinase and phosphatase activities to maintain a level of phosphorylated response regulator commensurate with the level of signal input. Signal input can be accommodated through stimulation of the kinase activity or the phosphatase activity of the two-component system. With some notable exceptions, the sensor kinases recognize a single stimulatory ligand. A new dimension in the regulation of two-component signal transduction systems was discovered in the Rap phosphatases which dephosphorylate the Spo0F response-regulator of Bacillus subtilis independent of the sensor kinases. This family of phosphatases is encoded by at least six chromosomal genes. Although not all of the phosphatases of the family have activity on phosphorylated Spo0F, the two best-characterized members, RapA and RapB, prevent sporulation by dephosphorylating this response regulator component of the phosphorelay. Phosphatase activity of RapA is regulated by a gene, phrA, in the same transcriptional unit, that encodes a peptide secreted from the cell which may serve as a quorum sensor. Most of the Rap phosphatase operons have a gene coding for a protein with some similarity to PhrA in their transcription units, but it is uncertain whether all of these play a role in regulation. The Rap phosphatases are postulated to be a mechanism for allowing signals other than those that affect the sensor kinases to regulate the signal transduction pathway. They may have been recruited to help regulate sporulation because the multiple signals regulating this process may out-strip the recognition capacity of the kinases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.1996.tb02460.x
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  • 9
    Electronic Resource
    Electronic Resource
    Identification of a second oligopeptide transport system in Bacillus subtilis and determination of its role in sporulation (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 13 (1994), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: SummarySporulation in Bacillus subtilis depends on an intact oligopeptide transport system, the Opp system. Mutants in opp sporulate poorly but second-site revertants can be found that restore sporulation and pep-tide transport. These second-site mutations were found in a second oligopeptide transport system, app, in which the peptide-binding protein, AppA, is mutant owing to a frame-shift mutation, and the revertants restore the original frame. The AppA mutation is present in the 168 strain of B. subtilis. The app operon consists of five genes in the order appD-appF-appA-appB-appC, with the locus designations corresponding to their homologue in the opp operon. Homology between the app and opp proteins ranges from 54% identity for AppF and OppF, to 22% identity for AppA and OppA. Both the App and Opp permease systems can transport tetra- and pentapeptides, but tripeptides are not transported by the App system. Strains of the genotype app+opp− are resistant to the tripeptide antibiotic bialaphos. The repaired App system can substitute completely for the Opp system in both sporulation and competence for genetic transformation. The pheno-types raised some speculation about the subunit configuration of the Opp system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2958.1994.tb00436.x
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  • 10
    Electronic Resource
    Electronic Resource
    KapB is a lipoprotein required for KinB signal transduction and activation of the phosphorelay to sporulation in Bacillus subtilis (1997)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 26 (1997), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: KinB is one of the two major histidine kinases that provide phosphate input in the phosphorelay to produce Spo0A∼P, the key transcription factor controlling the initiation of sporulation. A search for insertion mutants affected in activation of KinB-dependent sporulation led to the identification of the lgt locus encoding the lipoprotein glyceryltransferase required for the lipid modification of prolipoproteins before their cleavage and translocation across the cytoplasmic membrane. In parallel, a putative lipoprotein signal peptide cleavage site was detected in KapB, known to be strictly required for KinB-mediated sporulation and located downstream of KinB in a single transcription unit. Using PhoA peptide fusions, we have shown that KapB signal-peptide can direct active alkaline phosphatase to the outer surface of the cytoplasmic membrane in an LGT-dependent manner, strongly suggesting that KapB is a lipoprotein tethered to the outer face of the cytoplasmic membrane via a lipid anchor. As KapB proved to be dispensable for expression of the kinBkapB operon, a chimeric kinase was built consisting of KinA sensor domain fused to KinB kinase domain (KinA′-′B) to assess (i) the involvement of KapB in catalysis of the kinase reaction, and (ii) the ability of KinB to phosphorylate Spo0F in vitro. It was shown that KapB is dispensable for both in vivo and in vitro activation of the phosphorelay by the KinA′-′B chimera and that KinA′-′B phosphorylates Spo0F directly in vitro. Models for the role of KapB in regulating KinB activity are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.1997.6542024.x
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