scholarly journals Discovery of a New Neisseria gonorrhoeae Type IV Pilus Assembly Factor, TfpC

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Linda I. Hu ◽  
Shaohui Yin ◽  
Egon A. Ozer ◽  
Lee Sewell ◽  
Saima Rehman ◽  
...  

ABSTRACT Neisseria gonorrhoeae relies on type IV pili (T4p) to promote colonization of their human host and to cause the sexually transmitted infection gonorrhea. This organelle cycles through a process of extension and retraction back into the bacterial cell. Through a genetic screen, we identified the NGO0783 locus of N. gonorrhoeae strain FA1090 as containing a gene encoding a protein required to stabilize the type IV pilus in its extended, nonretracted conformation. We have named the gene tfpC and the protein TfpC. Deletion of tfpC produces a nonpiliated colony morphology, and immuno-transmission electron microscopy confirms that the pili are lost in the ΔtfpC mutant, although there is some pilin detected near the bacterial cell surface. A copy of the tfpC gene expressed from a lac promoter restores pilus expression and related phenotypes. A ΔtfpC mutant shows reduced levels of pilin protein, but complementation with a tfpC gene restored pilin to normal levels. Bioinformatic searches show that there are orthologues in numerous bacterial species, but not all type IV pilin-expressing bacteria contain orthologous genes. Coevolution and nuclear magnetic resonance (NMR) analysis indicates that TfpC contains an N-terminal transmembrane helix, a substantial extended/unstructured region, and a highly charged C-terminal coiled-coil domain. IMPORTANCE Most bacterial species express one or more extracellular organelles called pili/fimbriae that are required for many properties of each bacterial cell. The Neisseria gonorrhoeae type IV pilus is a major virulence and colonization factor for the sexually transmitted infection gonorrhea. We have discovered a new protein of Neisseria gonorrhoeae called TfpC that is required to maintain type IV pili on the bacterial cell surface. There are similar proteins found in other members of the Neisseria genus and many other bacterial species important for human health.

2020 ◽  
Author(s):  
Linda I. Hu ◽  
Shaohui Yin ◽  
Egon A. Ozer ◽  
Lee Sewell ◽  
Saima Rehman ◽  
...  

AbstractNeisseria gonorrhoeae rely on Type IV pili (T4p) to promote colonization of their human host and to cause the sexually transmitted infection, gonorrhea. This organelle cycles through a process of extension and retraction back into the bacterial cell. Through a genetic screen, we identified the NGO0783 locus of N. gonorrhoeae strain FA1090 as containing a gene encoding a protein required to stabilize the Type IV pilus in its extended, non-retracted conformation. We have named the gene tfpC and the protein TfpC. Deletion of tfpC produces a nonpiliated colony morphology and immuno-transmission electron microscopy confirms that the pili are lost in the ΔtfpC mutant, although there is some pilin detected near the bacterial cell surface. A copy of the tfpC gene expressed from a lac promoter restores pilus expression and related phenotypes. A ΔtfpC mutant shows reduced levels of pilin protein, but complementation with a tfpC gene restored pilin to normal levels. Bioinformatic searches show there are orthologues in numerous bacteria species but not all Type IV pilin expressing bacteria contain orthologous genes. Co-evolution and NMR analysis indicates that TfpC contains an N-terminal transmembrane helix, a substantial extended/unstructured region and a highly charge C-terminal coiled-coil domain.ImportanceMost bacterial species express one or more extracellular organelles called pili/fimbriae that are required for many properties of each bacterial cell. The Neisseria gonorrhoeae Type IV pilus is a major virulence and colonization factor for the sexually transmitted infection, gonorrhea. We have discovered a new protein of Neisseria gonorrhoeae called TfpC that is required to maintain the Type IV pili on the bacterial cell surface. There are similar proteins found in the other members of the Neisseria genus and many other bacterial species important for human health.


mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Elizabeth A. Stohl ◽  
Erin M. Dale ◽  
Alison K. Criss ◽  
H. Steven Seifert

ABSTRACTThe sexually transmitted infection gonorrhea is caused exclusively by the human-specific pathogenNeisseria gonorrhoeae. Type IV pili are an essential virulence factor uniformly expressed on clinical gonococcal isolates and are required for several aspects of gonococcal pathogenesis, including adherence to host tissues, autoagglutination, twitching motility, and the uptake of DNA during transformation. Symptomatic gonococcal infection is characterized by the influx of neutrophils or polymorphonuclear leukocytes (PMNs) to the site of infection. PMNs are a key component of gonococcal pathogenesis, mediating the innate immune response through the use of oxidative and nonoxidative killing mechanisms. The M23B family zinc metallopeptidase NGO1686 is required for gonococci to survive oxidative killing by H2O2- and PMN-mediated killing through unknown mechanisms, but the only known target of NGO1686 is peptidoglycan. We report that the effect of NGO1686 on survival after exposure to H2O2and PMNs is mediated through its role in elaborating pili and that nonpiliated mutants ofN. gonorrhoeaeare less resistant to killing by H2O2, LL-37, and PMNs than the corresponding piliated strains. These findings add to the various virulence-associated functions attributable to gonococcal pili and may explain the selection basis for piliation in clinical isolates ofN. gonorrhoeae.IMPORTANCESuccessful infectious agents need to overcome host defense systems to establish infection. We show that theNeisseriapilus, a major virulence factor of this organism, which causes gonorrhea, helps protect the bacterium from two major killing mechanisms used by the host to combat infections. We also show that to express the pilus, an enzyme needs to partially degrade the cell wall of the bacterium.


2016 ◽  
Vol 198 (16) ◽  
pp. 2228-2235 ◽  
Author(s):  
Mark T. Anderson ◽  
Luke Byerly ◽  
Michael A. Apicella ◽  
H. Steven Seifert

ABSTRACTNeisseria gonorrhoeaecauses the human-specific disease gonorrhea and is transmitted from person to person primarily via sexual contact. During transmission,N. gonorrhoeaeis often exposed to seminal fluid and must adapt to this change in environment. Previous work demonstrated that seminal fluid facilitatesN. gonorrhoeaemotility and alters epithelial cell interactions. In this study, exposure to seminal fluid was found to decrease surface adherence of gonococci in a manner that was independent of Opa adhesin proteins or type IV pilus retraction. Semen was also shown to cause dispersal of bacteria that had previously established surface adherence. Although surface adherence decreased, interbacterial interactions were increased by seminal plasma both in long-term static culture and on a cell-to-cell basis over shorter time periods. The result of increased bacterium-bacterium interactions resulted in the formation of microcolonies, an important step in theN. gonorrhoeaeinfectious process. Seminal fluid also facilitated increased bacterial aggregation in the form of shear-resistant three-dimensional biofilms. These results emphasize the importance of the gonococcal response to the influx of seminal fluid within the genital niche. Further characterization of theN. gonorrhoeaeresponse to semen will advance our understanding of the mechanisms behind the establishment of infection in naive hosts and the process of transmission.IMPORTANCEN. gonorrhoeaeis the causative agent of the globally prevalent sexually transmitted infection gonorrhea. An understudied aspect of this human-adapted pathogen is the change in bacterial physiology that occurs during sexual transmission.N. gonorrhoeaeencounters semen when transmitted from host to host, and it is known that, whenN. gonorrhoeaeis exposed to seminal fluid, alterations in bacterial motility and type IV pilus arrangement occur. This work extends our previous observations on this modulation of gonococcal physiology by seminal fluid and demonstrates that seminal plasma decreases surface adherence, promotes interbacterial interactions, and enhances biofilm formation.


mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mark T. Anderson ◽  
Lena Dewenter ◽  
Berenike Maier ◽  
H. Steven Seifert

ABSTRACTNiche-restricted pathogens are evolutionarily linked with the specific biological fluids that are encountered during infection.Neisseria gonorrhoeaecauses the genital infection gonorrhea and is exposed to seminal fluid during sexual transmission. Treatment ofN. gonorrhoeaewith seminal plasma or purified semen proteins lactoferrin, serum albumin, and prostate-specific antigen each facilitated type IV pilus-mediated twitching motility of the bacterium. Motility in the presence of seminal plasma was characterized by high velocity and low directional persistence. In addition, infection of epithelial cells withN. gonorrhoeaein the presence of seminal plasma resulted in enhanced microcolony formation. Close association of multiple pili in the form of bundles was also disrupted after seminal plasma treatment leading to an increase in the number of single pilus filaments on the bacterial surface. Thus, exposure ofN. gonorrhoeaeto seminal plasma is proposed to alter bacterial motility and aggregation characteristics to influence the processes of transmission and colonization.IMPORTANCEThere are greater than 100 million estimated new cases of gonorrhea annually worldwide. Research characterizing the mechanisms of pathogenesis and transmission ofNeisseria gonorrhoeaeis important for developing new prevention strategies, since antibiotic resistance of the organism is becoming increasingly prevalent. Our work identifies seminal plasma as a mediator ofN. gonorrhoeaetwitching motility and microcolony formation through functional modification of the type IV pilus. These findings provide insight into motility dynamics and epithelial cell colonization under conditions that are relevant to sexual transmission. Type IV pili are common virulence factors with diverse functions among bacterial pathogens, and this work identifies interactions between type IV pili and the host environment. Finally, this work illustrates the importance of the host environment and niche-specific fluids on microbial pathogenesis.


2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Aretha Fiebig

ABSTRACTIn aquatic environments,Caulobacterspp. can be found at the boundary between liquid and air known as the neuston. I report an approach to study temporal features ofCaulobacter crescentuscolonization and pellicle biofilm development at the air-liquid interface and have defined the role of cell surface structures in this process. At this interface,C. crescentusinitially forms a monolayer of cells bearing a surface adhesin known as the holdfast. When excised from the liquid surface, this monolayer strongly adheres to glass. The monolayer subsequently develops into a three-dimensional structure that is highly enriched in clusters of stalked cells known as rosettes. As this pellicle film matures, it becomes more cohesive and less adherent to a glass surface. A mutant strain lacking a flagellum does not efficiently reach the surface, and strains lacking type IV pili exhibit defects in organization of the three-dimensional pellicle. Strains unable to synthesize the holdfast fail to accumulate at the boundary between air and liquid and do not form a pellicle. Phase-contrast images support a model whereby the holdfast functions to trapC. crescentuscells at the air-liquid boundary. Unlike the holdfast, neither the flagellum nor type IV pili are required forC. crescentusto partition to the air-liquid interface. While it is well established that the holdfast enables adherence to solid surfaces, this study provides evidence that the holdfast has physicochemical properties that allow partitioning of nonmotile mother cells to the air-liquid interface and facilitate colonization of this microenvironment.IMPORTANCEIn aquatic environments, the boundary at the air interface is often highly enriched with nutrients and oxygen. Colonization of this niche likely confers a significant fitness advantage in many cases. This study provides evidence that the cell surface adhesin known as a holdfast enablesCaulobacter crescentusto partition to and colonize the air-liquid interface. Additional surface structures, including the flagellum and type IV pili, are important determinants of colonization and biofilm formation at this boundary. Considering that holdfast-like adhesins are broadly conserved inCaulobacterspp. and other members of the diverse classAlphaproteobacteria, these surface structures may function broadly to facilitate colonization of air-liquid boundaries in a range of ecological contexts, including freshwater, marine, and soil ecosystems.


2020 ◽  
Vol 9 (21) ◽  
Author(s):  
Freda E.-C. Jen ◽  
Ibrahim M. El-Deeb ◽  
John M. Atack ◽  
Mark von Itzstein ◽  
Michael P. Jennings

ABSTRACT Neisseria gonorrhoeae causes the sexually transmitted infection gonorrhea. High-coverage (∼3,300-fold) transcriptome sequencing data have been collected from multidrug-resistant N. gonorrhoeae strain WHO Z grown in the presence and absence of PBT2.


mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Sara L. N. Kilmury ◽  
Lori L. Burrows

ABSTRACTMotility is an important virulence trait for many bacterial pathogens, allowing them to position themselves in appropriate locations at appropriate times. The motility structures type IV pili and flagella are also involved in sensing surface contact, which modulates pathogenicity. InPseudomonas aeruginosa, the PilS-PilR two-component system (TCS) regulates expression of the type IV pilus (T4P) major subunit PilA, while biosynthesis of the single polar flagellum is regulated by a hierarchical system that includes the FleSR TCS. Previous studies ofGeobacter sulfurreducensandDichelobacter nodosusimplicated PilR in regulation of non-T4P-related genes, including some involved in flagellar biosynthesis. Here we used transcriptome sequencing (RNA-seq) analysis to identify genes in addition topilAwith changes in expression in the absence ofpilR. Among the genes identified were 10 genes whose transcription increased in thepilAmutant but decreased in thepilRmutant, despite both mutants lacking T4P and pilus-related phenotypes. The products of these inversely dysregulated genes, many of which were hypothetical, may be important for virulence and surface-associated behaviors, as mutants had altered swarming motility, biofilm formation, type VI secretion system expression, and pathogenicity in a nematode model. Further, the PilSR TCS positively regulated transcription offleSR, and thus many genes in the FleSR regulon. As a result,pilSRdeletion mutants had defects in swimming motility that were independent of the loss of PilA. Together, these data suggest that in addition to controlling T4P expression, PilSR could have a broader role in the regulation ofP. aeruginosamotility and surface sensing behaviors.IMPORTANCESurface appendages such as type IV pili and flagella are important for establishing surface attachment and infection in a host in response to appropriate cues. The PilSR regulatory system that controls type IV pilus expression inPseudomonas aeruginosahas an established role in expression of the major pilin PilA. Here we provide evidence supporting a new role for PilSR in regulating flagellum-dependent swimming motility in addition to pilus-dependent twitching motility. Further, even though bothpilAandpilRmutants lack PilA and pili, we identified sets of genes downregulated in thepilRmutant and upregulated in apilAmutant as well as genes downregulated only in apilRmutant, independent of pilus expression. This finding suggests that change in the inner membrane levels of PilA is only one of the cues to which PilR responds to modulate gene expression. Identification of PilR as a regulator of multiple motility pathways may make it an interesting therapeutic target for antivirulence compounds.


mBio ◽  
2021 ◽  
Author(s):  
Alison K. Criss ◽  
Caroline A. Genco ◽  
Scott D. Gray-Owen ◽  
Ann E. Jerse ◽  
H Steven Seifert

The bacterium Neisseria gonorrhoeae (Ngo) is the main cause of the sexually transmitted infection gonorrhea. The global incidence of 87 million new Ngo infections each year, rising infection rates, and the emergence of Ngo strains that are resistant to all clinically recommended antibiotics have raised the specter of untreatable infections (M.


2020 ◽  
Vol 58 (11) ◽  
Author(s):  
Brian M. J. W. van der Veer ◽  
Christian J. P. A. Hoebe ◽  
Nicole H. T. M. Dukers-Muijrers ◽  
Lieke B. van Alphen ◽  
Petra F. G. Wolffs

ABSTRACT Neisseria gonorrhoeae is a common bacterial sexually transmitted infection (STI). Currently, there are limited data on the bacterial load in both men and women and on both genital and extragenital sites. Therefore, we quantified N. gonorrhoeae bacterial loads in a large population of women, heterosexual men, and men who have sex with men (MSM) at three different anatomical sites. N. gonorrhoeae-positive samples (n = 1265) of STI clinic consultations (n = 944) were tested for N. gonorrhoeae with the Roche Cobas 4800 system, and quantification cycle (Cq) values were used as an inversely proportional measure for N. gonorrhoeae bacterial load after interpolation from a standard curve. Bacterial loads were compared between sample materials and sexes using t tests. The following mean N. gonorrhoeae loads were observed: urine, 4.5 ± 1.0 log10 CFU/ml; vaginal swabs, 4.3 ± 1.1 log10 CFU/ml; anorectal swabs (women), 4.0 ± 1.2 log10 CFU/ml; anorectal swabs (men), 4.5 ± 1.3 log10 CFU/ml; oropharyngeal swabs (women), 2.8 ± 0.9 log10 CFU/ml; and oropharyngeal swabs (men), 3.2 ± 1.0 log10 CFU/ml. Oropharyngeal swabs had a significantly lower N. gonorrhoeae load (P < 0.001) than genital and anorectal samples. Loads did not differ between men and women. This is the first study that determined N. gonorrhoeae load in both women and men at three anatomical sites. The substantial N. gonorrhoeae load at all sample sites suggest that all sites may have transmission potential. However, the oropharyngeal site presents the lowest bacterial load. Men and women have a similar N. gonorrhoeae loads on separate anatomical sites, arguing for similar transmission potential and similar clinical relevance.


2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Courtney K. Ellison ◽  
Douglas B. Rusch ◽  
Yves V. Brun

ABSTRACT Surface appendages, such as flagella and type IV pili, mediate a broad range of bacterial behaviors, including motility, attachment, and surface sensing. While many species harbor both flagella and type IV pili, little is known about how or if their syntheses are coupled. Here, we show that deletions of genes encoding different flagellum machinery components result in a reduction of pilus synthesis in Caulobacter crescentus. First, we show that different flagellar mutants exhibit different levels of sensitivity to a pilus-dependent phage and that fewer cells within populations of flagellar mutants make pili. Furthermore, we find that single cells within flagellar mutant populations produce fewer pili per cell. We demonstrate that these gene deletions result in reduced transcription of pilus-associated genes and have a slight but significant effect on general transcription profiles. Finally, we show that the decrease in pilus production is due to a reduction in the pool of pilin subunits that are polymerized into pilus fibers. These data demonstrate that mutations in flagellar gene components not only affect motility but also can have considerable and unexpected consequences for other aspects of cell biology. IMPORTANCE Most bacterial species synthesize surface-exposed appendages that are important for environmental interactions and survival under diverse conditions. It is often assumed that these appendages act independently of each other and that mutations in either system can be used to assess functionality in specific processes. However, we show that mutations in flagellar genes can impact the production of type IV pili, as well as alter general RNA transcriptional profiles compared to a wild-type strain. These data demonstrate that seemingly simple mutations can broadly affect cell-regulatory networks.


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