scholarly journals CodY-Mediated Regulation of Guanosine Uptake in Bacillus subtilis

2011 ◽  
Vol 193 (22) ◽  
pp. 6276-6287 ◽  
Author(s):  
Boris R. Belitsky ◽  
Abraham L. Sonenshein

CodY is a global transcriptional regulator known to control expression of more than 100 genes and operons inBacillus subtilis. Some of the most strongly repressed targets of CodY, thenupNOPQ(formerly,yufNOPQ) genes, were found to encode a guanosine transporter. Using DNase I footprinting experiments, we identified two high-affinity CodY-binding sites in the regulatory region of thenupNgene. The two sites are located 50 bp upstream and 163 bp downstream of the transcription start site. The downstream site was responsible for 6- to 8-foldnupNrepression in the absence of the upstream site. When the upstream site was intact, however, only a minor contribution of the downstream site tonupNregulation could be detected under the conditions tested. Both sites contained 15-bp CodY-binding motifs with two mismatches each with respect to the consensus sequence, AATTTTCWGTTTTAA. However, the experimentally determined binding sites included additional sequences flanking the 15-bp CodY-binding motifs. An additional version of the 15-bp CodY-binding motif, with 5 mismatches with respect to the consensus but essential for efficient regulation by CodY, was found within the upstream site. The presence of multiple 15-bp motifs may be a common feature of CodY-binding sites.

2015 ◽  
Vol 197 (16) ◽  
pp. 2622-2630 ◽  
Author(s):  
Neus Sanchez-Alberola ◽  
Susana Campoy ◽  
David Emerson ◽  
Jordi Barbé ◽  
Ivan Erill

ABSTRACTThe SOS response is a transcriptional regulatory network governed by the LexA repressor that activates in response to DNA damage. In theBetaproteobacteria, LexA is known to target a palindromic sequence with the consensus sequence CTGT-N8-ACAG. We report the characterization of a LexA regulon in the iron-oxidizing betaproteobacteriumSideroxydans lithotrophicus.In silicoandin vitroanalyses show that LexA targets six genes by recognizing a binding motif with the consensus sequence GAACGaaCGTTC, which is strongly reminiscent of theBacillus subtilisLexA-binding motif. We confirm that the closely relatedGallionella capsiferriformansshares the same LexA-binding motif, andin silicoanalyses indicate that this motif is also conserved in theNitrosomonadalesand theMethylophilales. Phylogenetic analysis of LexA and the alpha subunit of DNA polymerase III (DnaE) reveal that the organisms harboring this noncanonical LexA form a compact taxonomic cluster within theBetaproteobacteria. However, theirlexAgene is unrelated to the standardBetaproteobacterialexA, and there is evidence of its spread through lateral gene transfer. In contrast to other reported cases of noncanonical LexA-binding motifs, the regulon ofS. lithotrophicusis comparable in size and function to that of many otherBetaproteobacteria, suggesting that a convergent SOS regulon has reevolved under the control of a new LexA protein. Analysis of the DNA-binding domain ofS. lithotrophicusLexA reveals little sequence similarity with that of other LexA proteins targeting similar binding motifs, suggesting that network structure may limit site evolution or that structural constrains make theB. subtilis-type motif an optimal interface for multiple LexA sequences.IMPORTANCEUnderstanding the evolution of transcriptional systems enables us to address important questions in microbiology, such as the emergence and transfer potential of different regulatory systems to regulate virulence or mediate responses to stress. The results reported here constitute the first characterization of a noncanonical LexA protein regulating a standard SOS regulon. This is significant because it illustrates how a complex transcriptional program can be put under the control of a novel transcriptional regulator. Our results also reveal a substantial degree of plasticity in the LexA recognition domain, raising intriguing questions about the space of protein-DNA interfaces and the specific evolutionary constrains faced by these elements.


mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Aisha T. Burton ◽  
Aaron DeLoughery ◽  
Gene-Wei Li ◽  
Daniel B. Kearns

ABSTRACT Laboratory strains of Bacillus subtilis encode many alternative sigma factors, each dedicated to expressing a unique regulon such as those involved in stress resistance, sporulation, and motility. The ancestral strain of B. subtilis also encodes an additional sigma factor homolog, ZpdN, not found in lab strains due to being encoded on the large, low-copy-number plasmid pBS32, which was lost during domestication. DNA damage triggers pBS32 hyperreplication and cell death in a manner that depends on ZpdN, but how ZpdN mediates these effects is unknown. Here, we show that ZpdN is a bona fide sigma factor that can direct RNA polymerase to transcribe ZpdN-dependent genes, and we rename ZpdN SigN accordingly. Rend-seq (end-enriched transcriptome sequencing) analysis was used to determine the SigN regulon on pBS32, and the 5′ ends of transcripts were used to predict the SigN consensus sequence. Finally, we characterize the regulation of SigN itself and show that it is transcribed by at least three promoters: PsigN1, a strong SigA-dependent LexA-repressed promoter; PsigN2, a weak SigA-dependent constitutive promoter; and PsigN3, a SigN-dependent promoter. Thus, in response to DNA damage SigN is derepressed and then experiences positive feedback. How cells die in a pBS32-dependent manner remains unknown, but we predict that death is the product of expressing one or more genes in the SigN regulon. IMPORTANCE Sigma factors are utilized by bacteria to control and regulate gene expression. Some sigma factors are activated during times of stress to ensure the survival of the bacterium. Here, we report the presence of a sigma factor that is encoded on a plasmid that leads to cellular death after DNA damage.


2010 ◽  
Vol 24 (5) ◽  
pp. 898-913 ◽  
Author(s):  
Sarah Denayer ◽  
Christine Helsen ◽  
Lieven Thorrez ◽  
Annemie Haelens ◽  
Frank Claessens

Abstract The androgen receptor (AR) and glucocorticoid, progestagen, and mineralocorticoid receptors all recognize classical DNA response elements that are organized as inverted repeats of 5′-AGAACA-3′-like motifs with a three-nucleotide spacer. Next to such elements, the AR also recognizes a second type of androgen response element (ARE), the so-called selective AREs, which resemble more the direct repeats of the same hexamer. In this work, we show that not only the AR but also the progestagen receptor can recognize the selective AREs, whereas neither glucocorticoid nor mineralocorticoid receptor can. Recently, genomic AR-binding fragments have been postulated to contain AR-binding sites that diverge considerably from the classical ARE consensus. Extensive mutational analyses of these candidate motifs, however, reinstalls the values of the consensus sequence for the AREs as mentioned above, the importance of their dimeric nature and the presence of exactly three-nucleotide spacing. We developed a position-specific probability matrix that was used to predict with higher accuracy new AREs in different AR-binding regions. So far, all AR-binding genomic fragments that were analyzed contain AREs defined as receptor-dimer binding motifs with the ability to confer responsiveness to a reporter gene.


2005 ◽  
Vol 187 (22) ◽  
pp. 7655-7666 ◽  
Author(s):  
Nora Au ◽  
Elke Kuester-Schoeck ◽  
Veena Mandava ◽  
Laura E. Bothwell ◽  
Susan P. Canny ◽  
...  

ABSTRACT The SOS response in bacteria includes a global transcriptional response to DNA damage. DNA damage is sensed by the highly conserved recombination protein RecA, which facilitates inactivation of the transcriptional repressor LexA. Inactivation of LexA causes induction (derepression) of genes of the LexA regulon, many of which are involved in DNA repair and survival after DNA damage. To identify potential RecA-LexA-regulated genes in Bacillus subtilis, we searched the genome for putative LexA binding sites within 300 bp upstream of the start codons of all annotated open reading frames. We found 62 genes that could be regulated by putative LexA binding sites. Using mobility shift assays, we found that LexA binds specifically to DNA in the regulatory regions of 54 of these genes, which are organized in 34 putative operons. Using DNA microarray analyses, we found that 33 of the genes with LexA binding sites exhibit RecA-dependent induction by both mitomycin C and UV radiation. Among these 33 SOS genes, there are 22 distinct LexA binding sites preceding 18 putative operons. Alignment of the distinct LexA binding sites reveals an expanded consensus sequence for the B. subtilis operator: 5′-CGAACATATGTTCG-3′. Although the number of genes controlled by RecA and LexA in B. subtilis is similar to that of Escherichia coli, only eight B. subtilis RecA-dependent SOS genes have homologous counterparts in E. coli.


1993 ◽  
Vol 13 (7) ◽  
pp. 4049-4056
Author(s):  
A Kobayashi ◽  
M Matsui ◽  
T Kubo ◽  
S Natori

Various Sarcophaga peregrina (flesh fly) defense protein genes were shown to be activated when NIH-Sape-4 cells were cultured with bacterial lipopolysaccharides or beta-1,3-glucan. The 5' upstream regions of the defense protein genes were found to have common motifs showing similarity to the mammalian NF-kappa B-binding consensus sequence. A protein with affinity to the NF-kappa B-binding motif of the Sarcophaga lectin promoter was identified and purified to near homogeneity. This 59-kDa protein also bound to the NF-kappa B-binding motifs of other defense protein genes, e.g., sarcotoxin I and sarcotoxin II genes. This protein was found in both the cytoplasmic and the nuclear fractions of the cells, and it appeared to migrate from the cytoplasm to the nucleus on treatment of the cells with lipopolysaccharides. This 59-kDa protein is probably a transcriptional regulator of the genes for defense proteins of S. peregrina.


1989 ◽  
Vol 9 (6) ◽  
pp. 2431-2444
Author(s):  
K Yu ◽  
R T Elder

Fragments from the Ty-D15 element of Saccharomyces cerevisiae were assayed for the ability to direct 3'-end formation for RNA initiated by the GAL1 promoter. The delta, the direct repeat at each end of the element, was capable of forming 3' ends at two sites, an inefficient upstream site and an efficient downstream site near the end of the delta. Different sequences were required for 3'-end formation at these sites. For the efficient site, all transcripts had 3' ends in the delta and no downstream transcription was detected, which suggested that these sequences terminate transcription. Surprisingly, the delta region downstream of the initiation site for Ty RNA comprised part of this major site and terminated more than 50% of the transcripts that read into it. Sequences necessary for the efficient site were localized to two small regions. Both regions were upstream of the 3' end and contained similarities to a tripartite consensus sequence that has been proposed as a terminator element. Sequences near the position of the 3' end could also affect termination; a short G + C-rich sequence inserted just downstream changed an efficient terminator to an inefficient one. Initiation in the delta had no effect on the efficiency or positions or termination in that delta. A new initiation site was seen when the same delta terminated transcription, but transcriptional interference did not occur, since the amount of initiation was not decreased.


2011 ◽  
Vol 193 (22) ◽  
pp. 6366-6374 ◽  
Author(s):  
Arnaud Chastanet ◽  
Richard Losick

The response regulator Spo0A governs multiple developmental processes inBacillus subtilis, including most conspicuously sporulation. Spo0A is activated by phosphorylation via a multicomponent phosphorelay. Previous work has shown that the Spo0A protein is not rate limiting for sporulation. Rather, Spo0A is present at high levels in growing cells, rapidly rising to yet higher levels under sporulation-inducing conditions, suggesting that synthesis of the response regulator is subject to a just-in-time control mechanism. Transcription ofspo0Ais governed by a promoter switching mechanism, involving a vegetative, σA-recognized promoter, Pv, and a sporulation σH-recognized promoter, Ps, that is under phosphorylated Spo0A (Spo0A∼P) control. Thespo0Aregulatory region also contains four (including one identified in the present work) conserved elements that conform to the consensus binding site for Spo0A∼P binding sites. These are herein designated O1, O2, O3, and O4in reverse order of their proximity to the coding sequence. Here we report that O1is responsible for repressing Pvduring the transition to stationary phase, that O2is responsible for repressing Psduring growth, that O3is responsible for activating Psat the start of sporulation, and that O4is dispensable for promoter switching. We also report that Spo0A synthesis is subject to a posttranscriptional control mechanism such that translation of mRNAs originating from Pvis impeded due to RNA secondary structure whereas mRNAs originating from Psare fully competent for protein synthesis. We propose that the opposing actions of O2and O3and the enhanced translatability of mRNAs originating from Pscreate a highly sensitive, self-reinforcing switch that is responsible for producing a burst of Spo0A synthesis at the start of sporulation.


2002 ◽  
Vol 68 (3) ◽  
pp. 1102-1108 ◽  
Author(s):  
Sau-Ching Wu ◽  
Sui-Lam Wong

ABSTRACT Streptavidin is a biotin-binding protein which has been widely used in many in vitro and in vivo applications. Because of the ease of protein recovery and availability of protease-deficient strains, the Bacillus subtilis expression-secretion system is an attractive system for streptavidin production. However, attempts to produce streptavidin using B. subtilis face the problem that cells overproducing large amounts of streptavidin suffer poor growth, presumably because of biotin deficiency. This problem cannot be solved by supplementing biotin to the culture medium, as this will saturate the biotin binding sites in streptavidin. We addressed this dilemma by engineering a B. subtilis strain (WB800BIO) which overproduces intracellular biotin. The strategy involves replacing the natural regulatory region of the B. subtilis chromosomal biotin biosynthetic operon (bioWAFDBIorf2) with an engineered one consisting of the B. subtilis groE promoter and gluconate operator. Biotin production in WB800BIO is induced by gluconate, and the level of biotin produced can be adjusted by varying the gluconate dosage. A level of gluconate was selected to allow enhanced intracellular production of biotin without getting it released into the culture medium. WB800BIO, when used as a host for streptavidin production, grows healthily in a biotin-limited medium and produces large amounts (35 to 50 mg/liter) of streptavidin, with over 80% of its biotin binding sites available for future applications.


1989 ◽  
Vol 9 (6) ◽  
pp. 2431-2444 ◽  
Author(s):  
K Yu ◽  
R T Elder

Fragments from the Ty-D15 element of Saccharomyces cerevisiae were assayed for the ability to direct 3'-end formation for RNA initiated by the GAL1 promoter. The delta, the direct repeat at each end of the element, was capable of forming 3' ends at two sites, an inefficient upstream site and an efficient downstream site near the end of the delta. Different sequences were required for 3'-end formation at these sites. For the efficient site, all transcripts had 3' ends in the delta and no downstream transcription was detected, which suggested that these sequences terminate transcription. Surprisingly, the delta region downstream of the initiation site for Ty RNA comprised part of this major site and terminated more than 50% of the transcripts that read into it. Sequences necessary for the efficient site were localized to two small regions. Both regions were upstream of the 3' end and contained similarities to a tripartite consensus sequence that has been proposed as a terminator element. Sequences near the position of the 3' end could also affect termination; a short G + C-rich sequence inserted just downstream changed an efficient terminator to an inefficient one. Initiation in the delta had no effect on the efficiency or positions or termination in that delta. A new initiation site was seen when the same delta terminated transcription, but transcriptional interference did not occur, since the amount of initiation was not decreased.


1993 ◽  
Vol 13 (7) ◽  
pp. 4049-4056 ◽  
Author(s):  
A Kobayashi ◽  
M Matsui ◽  
T Kubo ◽  
S Natori

Various Sarcophaga peregrina (flesh fly) defense protein genes were shown to be activated when NIH-Sape-4 cells were cultured with bacterial lipopolysaccharides or beta-1,3-glucan. The 5' upstream regions of the defense protein genes were found to have common motifs showing similarity to the mammalian NF-kappa B-binding consensus sequence. A protein with affinity to the NF-kappa B-binding motif of the Sarcophaga lectin promoter was identified and purified to near homogeneity. This 59-kDa protein also bound to the NF-kappa B-binding motifs of other defense protein genes, e.g., sarcotoxin I and sarcotoxin II genes. This protein was found in both the cytoplasmic and the nuclear fractions of the cells, and it appeared to migrate from the cytoplasm to the nucleus on treatment of the cells with lipopolysaccharides. This 59-kDa protein is probably a transcriptional regulator of the genes for defense proteins of S. peregrina.


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