Properties and Biological Role of Streptococcal Fratricins

Berg, Kari Helene; Biørnstad, Truls Johan; Johnsborg, Ola; Håvarstein, Leiv Sigve

doi:10.1128/aem.00098-12

Cited by 33 publications

(35 citation statements)

References 78 publications

(111 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Downstream of a CIN-box promoter we identified a fratricin-like gene in S. suis (SSU1911) that contains an N-terminal CHAP (Cysteine, Histidine-dependent Amidohydrolases/Peptidases) domain and two SH3b (central Src homology 3b) domains, which are also present in pneumococcal fratricin (Berg et al, 2012). After induction of S. suis competence by XIP, a gene encoding a homolog of fratricin was up-regulated at 5, 15, and 45 min by 722-, 208-, and 22-fold, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The expression profile of this gene was similar to the expression profile of the ComX-regulated genes of S. suis (Figure 4) suggesting that S. suis also produces a fratricin-like protein during competence development. S. pneumoniae fratricin, a cell wall hydrolase, was shown to lyse non-competent pneumococci and closely related bacterial species, thereby ensuring that the transforming DNA has overall a high level of homology to the competent recipients, favoring beneficial DNA recombination over detrimental genetic events (Kausmally et al, 2005; Håvarstein et al, 2006; Claverys et al, 2007; Berg et al, 2012). We speculate that the S. suis fratricin-like protein may have a similar role to that of pneumococcal fratricin, although we could not identify a homolog of the candidate fratricin immunity gene ComM, described in S. pneumoniae (Håvarstein et al, 2006; Eldholm et al, 2010).…”

Section: Resultsmentioning

confidence: 99%

“…Conservation of this predatory mechanism has been proposed in other streptococci based on gene homologies and the presence of CIN-boxes in promoter regions (Berg et al, 2012). Recently, in S. mutans a bacteriocin-like molecule was identified that is induced by its competence-inducing peptide, causing autolysis in part of the population (Perry et al, 2009; Lemme et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

Zaccaria

Wels²,

Baarlen

et al. 2016

Front. Microbiol.

View full text Add to dashboard Cite

In S. suis the ComX-inducing peptide (XIP) pheromone regulates ComR-dependent transcriptional activation of comX (or sigX) the regulator of the late competence regulon. The aims of this study were to identify the ComR-regulated genes and in S. suis using genome-wide transcriptomics and identify their function based on orthology and the construction of specific knockout mutants. The ComX regulon we identified, includes all homologs of the “transformasome” a type 4-like pilus DNA binding and transport apparatus identified in Streptococcus pneumoniae, Streptococcus mutans, and Streptococcus thermophilus. A conserved CIN-box (YTACGAAYW), predicted to be bound by ComX, was found in the promoters of operons encoding genes involved in expression of the transformasome. Mutants lacking the major pilin gene comYC were not transformable demonstrating that the DNA uptake pilus is indeed required for competence development in S. suis. Competence was a transient state with the comX regulon shut down after ~15 min even when transcription of comX had not returned to basal levels, indicating other mechanisms control the exit from competence. The ComX regulon also included genes involved in DNA repair including cinA which we showed to be required for high efficiency transformation. In contrast to S. pneumoniae and S. mutans the ComX regulon of S. suis did not include endA which converts the transforming DNA into ssDNA, or ssbA, which protects the transforming ssDNA from degradation. EndA appeared to be essential in S. suis so we could not generate mutants and confirm its role in DNA transformation. Finally, we identified a putative homolog of fratricin, and a putative bacteriocin gene cluster, that were also part of the CIN-box regulon and thus may play a role in DNA release from non-competent cells, enabling gene transfer between S. suis pherotypes or S. suis and other species. S. suis mutants of oppA, the binding subunit of the general oligopeptide transporter were not transformable, suggesting that it is required for the import of XIP.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

Zaccaria

Wels²,

Baarlen

et al. 2016

Front. Microbiol.

View full text Add to dashboard Cite

show abstract

“…Competent cells of S. pneumoniae produce cell wall hydrolases, so-called fratricins, which are secreted by the competent subpopulation and kill the non-competent brothers-hence the name (Berg et al, 2012;Wei and Havarstein, 2012). In S. mutans, the gene SMU.836 is 100% identical to cbpD, the key fratricin of S. pneumoniae.…”

Section: Cultivation Mediummentioning

confidence: 99%

Cross-feeding and interkingdom communication in dual-species biofilms of Streptococcus mutans and Candida albicans

et al. 2014

View full text Add to dashboard Cite

Polymicrobial biofilms are of large medical importance, but relatively little is known about the role of interspecies interactions for their physiology and virulence. Here, we studied two human pathogens co-occuring in the oral cavity, the opportunistic fungus Candida albicans and the caries-promoting bacterium Streptococcus mutans. Dual-species biofilms reached higher biomass and cell numbers than mono-species biofilms, and the production of extracellular polymeric substances (EPSs) by S. mutans was strongly suppressed, which was confirmed by scanning electron microscopy, gas chromatography-mass spectrometry and transcriptome analysis. To detect interkingdom communication, C. albicans was co-cultivated with a strain of S. mutans carrying a transcriptional fusion between a green fluorescent protein-encoding gene and the promoter for sigX, the alternative sigma factor of S. mutans, which is induced by quorum sensing signals. Strong induction of sigX was observed in dual-species biofilms, but not in single-species biofilms. Conditioned media from mixed biofilms but not from C. albicans or S. mutans cultivated alone activated sigX in the reporter strain. Deletion of comS encoding the synthesis of the sigX-inducing peptide precursor abolished this activity, whereas deletion of comC encoding the competence-stimulating peptide precursor had no effect. Transcriptome analysis of S. mutans confirmed induction of comS, sigX, bacteriocins and the downstream late competence genes, including fratricins, in dual-species biofilms. We show here for the first time the stimulation of the complete quorum sensing system of S. mutans by a species from another kingdom, namely the fungus C. albicans, resulting in fundamentally changed virulence properties of the caries pathogen.

show abstract

“…With the exception of Streptococcus agalactiae, each species synthesizes a particular fratricin subtype that belongs to one of these families (2). Fratricins have varying but limited target ranges and are in general active against bacteria that are relatively closely related to the producer strain (3). Since they are encoded by late competence genes, fratricins are produced only when streptococci enter the competent state.…”

mentioning

confidence: 99%

Fratricide Is Essential for Efficient Gene Transfer between Pneumococci in Biofilms

Wei

Håvarstein

2012

Appl Environ Microbiol

Self Cite

View full text Add to dashboard Cite

ABSTRACTStreptococcus pneumoniaeand a number of commensal streptococcal species are competent for natural genetic transformation. The natural habitat of these bacteria is multispecies biofilms in the human oral cavity and nasopharynx. Studies investigating lateral transfer of virulence and antibiotic resistance determinants among streptococci have shown that interspecies as well as intraspecies gene exchange takes place in these environments. We have previously shown that the action of a competence-specific murein hydrolase termed CbpD strongly increases the rate of gene transfer between pneumococci grown in liquid cultures. CbpD is the key component of a bacteriolytic mechanism termed the fratricide mechanism. It is secreted by competent pneumococci and mediates the release of donor DNA from sensitive streptococci present in the same environment. However, in nature, gene exchange between streptococci takes place in biofilms and not in liquid cultures. In the present study, we therefore investigated whether CbpD affects the rate of gene transfer in laboratory-grown biofilms. Our results show that the fratricide mechanism has a strong positive impact on intrabiofilm gene exchange, indicating that it is important for active acquisition of homologous donor DNA under natural conditions. Furthermore, we found that competent biofilm cells ofS. pneumoniaeacquire a Novrmarker much more efficiently from neighboring cells than from the growth medium. Efficient lysis of target cells requires that CbpD act in conjunction with the murein hydrolase LytC. In contrast, the major autolysin LytA does not seem to be important for fratricide-mediated gene exchange in a biofilm environment.

show abstract

Properties and Biological Role of Streptococcal Fratricins

Cited by 33 publications

References 78 publications

Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

Temporal Regulation of the Transformasome and Competence Development in Streptococcus suis

Cross-feeding and interkingdom communication in dual-species biofilms of Streptococcus mutans and Candida albicans

Fratricide Is Essential for Efficient Gene Transfer between Pneumococci in Biofilms

Contact Info

Product

Resources

About