scholarly journals Cryptic prophage-encoded small protein DicB protects Escherichia coli from phage infection by inhibiting inner membrane receptor proteins

2019 ◽  
Author(s):  
Preethi T. Ragunathan ◽  
Carin K. Vanderpool
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Functional Characterization ◽  
Phage Infection ◽  
Gene Products ◽  
Bacterial Host ◽  
Host Chromosome ◽  
Small Protein ◽  
Bacterial Physiology ◽  
Bacteriophage Infection

AbstractBacterial genomes harbor cryptic prophages that have lost genes required for induction, excision from host chromosomes, or production of phage progeny. Escherichia coli K12 strains contain a cryptic prophage Qin that encodes a small RNA, DicF, and small protein, DicB, that have been implicated in control of bacterial metabolism and cell division. Since DicB and DicF are encoded in the Qin immunity region, we tested whether these gene products could protect the E. coli host from bacteriophage infection. Transient expression of the dicBF operon yielded cells that were ~100-fold more resistant to infection by λ phage than control cells, and the phenotype was DicB-dependent. DicB specifically inhibited infection by λ and other phages that use ManYZ membrane proteins for cytoplasmic entry of phage DNA. In addition to blocking ManYZ-dependent phage infection, DicB also inhibited the canonical sugar transport activity of ManYZ. Previous studies demonstrated that DicB interacts with MinC, an FtsZ polymerization inhibitor, causing MinC localization to mid-cell and preventing Z ring formation and cell division. In strains producing mutant MinC proteins that do not interact with DicB, both DicB-dependent phenotypes involving ManYZ were lost. These results suggest that DicB is a pleiotropic regulator of bacterial physiology and cell division, and that these effects are mediated by a key molecular interaction with the cell division protein MinC.ImportanceTemperate bacteriophages can integrate their genomes into the bacterial host chromosome and exist as prophages whose gene products play key roles in bacterial fitness and interactions with eukaryotic host organisms. Most bacterial chromosomes contain “cryptic” prophages that have lost genes required for production of phage progeny but retain genes of unknown function that may be important for regulating bacterial host physiology. This study provides such an example – where a cryptic prophage-encoded product can perform multiple roles in the bacterial host and influence processes including metabolism, cell division, and susceptibility to phage infection. Further functional characterization of cryptic prophage-encoded functions will shed new light on host-phage interactions and their cellular physiological implications.

scholarly journals Cryptic-Prophage-Encoded Small Protein DicB Protects Escherichia coli from Phage Infection by Inhibiting Inner Membrane Receptor Proteins

2019 ◽  
Vol 201 (23) ◽  
Author(s):  
Preethi T. Ragunathan ◽  
Carin K. Vanderpool
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Phage Infection ◽  
Gene Products ◽  
Bacterial Host ◽  
Host Chromosome ◽  
Small Protein ◽  
Content Type ◽  
Bacterial Physiology ◽  
K 12

ABSTRACT Bacterial genomes harbor cryptic prophages that have lost genes required for induction, excision from host chromosomes, or production of phage progeny. Escherichia coli K-12 strains contain a cryptic prophage, Qin, that encodes a small RNA, DicF, and a small protein, DicB, that have been implicated in control of bacterial metabolism and cell division. Since DicB and DicF are encoded in the Qin immunity region, we tested whether these gene products could protect the E. coli host from bacteriophage infection. Transient expression of the dicBF operon yielded cells that were ∼100-fold more resistant to infection by λ phage than control cells, and the phenotype was DicB dependent. DicB specifically inhibited infection by λ and other phages that use ManYZ membrane proteins for cytoplasmic entry of phage DNA. In addition to blocking ManYZ-dependent phage infection, DicB also inhibited the canonical sugar transport activity of ManYZ. Previous studies demonstrated that DicB interacts with MinC, an FtsZ polymerization inhibitor, causing MinC localization to midcell and preventing Z ring formation and cell division. In strains producing mutant MinC proteins that do not interact with DicB, both DicB-dependent phenotypes involving ManYZ were lost. These results suggest that DicB is a pleiotropic regulator of bacterial physiology and cell division and that these effects are mediated by a key molecular interaction with the cell division protein MinC. IMPORTANCE Temperate bacteriophages can integrate their genomes into the bacterial host chromosome and exist as prophages whose gene products play key roles in bacterial fitness and interactions with eukaryotic host organisms. Most bacterial chromosomes contain “cryptic” prophages that have lost genes required for production of phage progeny but retain genes of unknown function that may be important for regulating bacterial host physiology. This study provides such an example, where a cryptic-prophage-encoded product can perform multiple roles in the bacterial host and influence processes, including metabolism, cell division, and susceptibility to phage infection. Further functional characterization of cryptic-prophage-encoded functions will shed new light on host-phage interactions and their cellular physiological implications.

scholarly journals Xenogeneic modulation of the ClpCP protease of Bacillus subtilis by a phage-encoded adaptor-like protein

2019 ◽  
Vol 294 (46) ◽  
pp. 17501-17511 ◽  
Author(s):  
Nancy Mulvenna ◽  
Ingo Hantke ◽  
Lynn Burchell ◽  
Sophie Nicod ◽  
David Bell ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Gene Products ◽  
Bacterial Host ◽  
Systematic Analysis ◽  
Phage Gene ◽  
Cellular Processes ◽  
Bacteriophage Infection ◽  
Archaeal Viruses ◽  
Cytotoxic Proteins ◽  
Cellular Pathways

Like eukaryotic and archaeal viruses, which coopt the host's cellular pathways for their replication, bacteriophages have evolved strategies to alter the metabolism of their bacterial host. SPO1 bacteriophage infection of Bacillus subtilis results in comprehensive remodeling of cellular processes, leading to conversion of the bacterial cell into a factory for phage progeny production. A cluster of 26 genes in the SPO1 genome, called the host takeover module, encodes for potentially cytotoxic proteins that specifically shut down various processes in the bacterial host, including transcription, DNA synthesis, and cell division. However, the properties and bacterial targets of many genes of the SPO1 host takeover module remain elusive. Through a systematic analysis of gene products encoded by the SPO1 host takeover module, here we identified eight gene products that attenuated B. subtilis growth. Of the eight phage gene products that attenuated bacterial growth, a 25-kDa protein called Gp53 was shown to interact with the AAA+ chaperone protein ClpC of the ClpCP protease of B. subtilis. Our results further reveal that Gp53 is a phage-encoded adaptor-like protein that modulates the activity of the ClpCP protease to enable efficient SPO1 phage progeny development. In summary, our findings indicate that the bacterial ClpCP protease is the target of xenogeneic (dys)regulation by a SPO1 phage–derived factor and add Gp53 to the list of antibacterial products that target bacterial protein degradation and therefore may have utility for the development of novel antibacterial agents.

scholarly journals Survival Strategies of Streptococcus pyogenes in Response to Phage Infection

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 612
Author(s):  
Dior Beerens ◽  
Sandra Franch-Arroyo ◽  
Timothy J. Sullivan ◽  
Christian Goosmann ◽  
Volker Brinkmann ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Membrane Vesicles ◽  
Phage Infection ◽  
Survival Strategies ◽  
Modular Organization ◽  
Lytic Phage ◽  
Bacterial Host ◽  
Host Chromosome ◽  
Double Stranded Dna ◽  
Insight Into

Bacteriophages exert strong evolutionary pressure on their microbial hosts. In their lytic lifecycle, complete bacterial subpopulations are utilized as hosts for bacteriophage replication. However, during their lysogenic lifecycle, bacteriophages can integrate into the host chromosome and alter the host’s genomic make-up, possibly resulting in evolutionary important adjustments. Not surprisingly, bacteria have evolved sophisticated immune systems to protect against phage infection. Streptococcus pyogenes isolates are frequently lysogenic and their prophages have been shown to be major contributors to the virulence of this pathogen. Most S. pyogenes phage research has focused on genomic prophages in relation to virulence, but little is known about the defensive arsenal of S. pyogenes against lytic phage infection. Here, we characterized Phage A1, an S. pyogenes bacteriophage, and investigated several mechanisms that S. pyogenes utilizes to protect itself against phage predation. We show that Phage A1 belongs to the Siphoviridae family and contains a circular double-stranded DNA genome that follows a modular organization described for other streptococcal phages. After infection, the Phage A1 genome can be detected in isolated S. pyogenes survivor strains, which enables the survival of the bacterial host and Phage A1 resistance. Furthermore, we demonstrate that the type II-A CRISPR-Cas system of S. pyogenes acquires new spacers upon phage infection, which are increasingly detectable in the absence of a capsule. Lastly, we show that S. pyogenes produces membrane vesicles that bind to phages, thereby limiting the pool of phages available for infection. Altogether, this work provides novel insight into survival strategies employed by S. pyogenes to combat phage predation.

scholarly journals Ribonucleic acid synthesis by Escherichia coli C3000/L after infection by the ribonucleic acid coliphage ZIK/1, and properties of coliphage-ZIK/1 ribonucleic acid

1965 ◽  
Vol 97 (1) ◽  
pp. 17-26 ◽  
Author(s):  
DHL Bishop
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Ribonucleic Acid ◽  
Sedimentation Coefficient ◽  
Cell Lysis ◽  
Acid Synthesis ◽  
Physical Characteristics ◽  
Ribosome Synthesis ◽  
Bacteriophage Infection

1. A method is described for the preparation and purification of the RNA from the RNA coliphage ZIK/1. 2. Some of the physical characteristics and infective properties of coliphage-ZIK/1 RNA were examined. 3. A method is also described for examining the type and quantity of RNA synthesized after bacteriophage infection. 4. Ribosome synthesis was decreased 15min. after bacteriophage adsorption, bacteriophage RNA was synthesized from 15min. to 120min. after adsorption and intracellular bacteriophages appeared 40min. after adsorption. Cell lysis commenced 60min. after adsorption, and was half complete 20min. later and 90-95% complete 120min. after adsorption. 5. Cell division continued until 40min. after bacteriophage adsorption. 6. Bacterial ribosomes were conserved during the infective process. 7. Intracellular bacteriophage RNA has sedimentation coefficient 28s but after cell lysis it has sedimentation coefficient 10-5s.

scholarly journals Inactivation of Cell Division Protein FtsZ by SulA Makes Lon Indispensable for the Viability of a ppGpp0Strain of Escherichia coli

2015 ◽  
Vol 198 (4) ◽  
pp. 688-700 ◽  
Author(s):  
Aanisa Nazir ◽  
Rajendran Harinarayanan
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Model Organism ◽  
Stringent Response ◽  
Physiological Significance ◽  
Lon Protease ◽  
Rich Medium ◽  
Content Type ◽  
Bacterial Physiology ◽  
Stress Changes

ABSTRACTThe modified nucleotides (p)ppGpp play an important role in bacterial physiology. While the accumulation of the nucleotides is vital for adaptation to various kinds of stress, changes in the basal level modulates growth rate and vice versa. Studying the phenotypes unique to the strain lacking (p)ppGpp (ppGpp0) under overtly unstressed growth conditions may be useful to understand functions regulated by basal levels of (p)ppGpp and its physiological significance. In this study, we show that the ppGpp0strain, unlike the wild type, requires the Lon protease for cell division and viability in LB. Our results indicate the decrease in FtsZ concentration in the ppGpp0strain makes cell division vulnerable to SulA inhibition. We did not find evidence for SOS induction contributing to the cell division defect in the ppGpp0Δlonstrain. Based on the results, we propose that basal levels of (p)ppGpp are required to sustain normal cell division inEscherichia coliduring growth in rich medium and that the basal SulA level set by Lon protease is important for insulating cell division against a decrease in FtsZ concentration and conditions that can increase the susceptibility of FtsZ to SulA.IMPORTANCEThe physiology of the stringent response has been the subject of investigation for more than 4 decades, with the majority of the work carried out using the bacterial model organismEscherichia coli. These studies have revealed that the accumulation of (p)ppGpp, the effector of the stringent response, is associated with growth retardation and changes in gene expression that vary with the intracellular concentration of (p)ppGpp. By studying a synthetic lethal phenotype, we have uncovered a function modulated by the basal levels of (p)ppGpp and studied its physiological significance. Our results show that (p)ppGpp and Lon protease contribute to the robustness of the cell division machinery inE. coliduring growth in rich medium.

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