Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Gene Regulation During Sporulation

Gene Regulation During Sporulation

Sporulation is a complex developmental process that allows certain Gram-positive bacteria, such as Bacillus subtilis and Clostridium species, to survive extreme environmental conditions. This process is tightly regulated by a series of signaling cascades and transcriptional controls, ensuring the formation of a highly resistant endospore.Sporulation is triggered by unfavorable conditions, such as nutrient depletion, and is governed by a phosphorelay system. One of the sensor kinases, such as...

Regulation of Bacterial Virulence

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...

Determinants of Bacterial Pathogenicity and Virulence

Determinants of Bacterial Pathogenicity and Virulence

Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...

Streptococcal Pharyngitis

Streptococcal Pharyngitis

Streptococcal pharyngitis, commonly known as “strep throat,” is an acute infection of the oropharyngeal tissues caused by the Gram‑positive Group A Streptococcus (Streptococcus pyogenes). Transmission occurs primarily through respiratory droplets expelled during coughing, sneezing, or talking.Mechanisms of Host Entry and Immune EvasionUpon entering the host, S. pyogenes adheres to the mucosal epithelial cells of the pharynx via surface proteins, notably lipoteichoic acid and the antiphagocytic...

Gene Regulation in Microbial Communities: Quorum Sensing

Gene Regulation in Microbial Communities: Quorum Sensing

Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...

Global Regulatory Systems

Global Regulatory Systems

Global regulatory systems in bacteria enable rapid and coordinated responses to environmental changes by integrating sensory inputs with gene expression, ensuring efficient adaptation to fluctuating conditions. Key global regulatory mechanisms include regulons, two-component systems, sigma factors, and secondary messengers.Regulons and Global RegulatorsA regulon is a collection of genes and operons controlled by a common global regulator. These regulators enable bacteria to prioritize resource...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Temporal and spatial regulation of protein cross-linking by the pre-assembled substrates of a Bacillus subtilis spore coat transglutaminase.

PLoS genetics·2019

Same author

A LysM Domain Intervenes in Sequential Protein-Protein and Protein-Peptidoglycan Interactions Important for Spore Coat Assembly in <i>Bacillus subtilis</i>.

Journal of bacteriology·2018

Same author

SpoVID functions as a non-competitive hub that connects the modules for assembly of the inner and outer spore coat layers in Bacillus subtilis.

Molecular microbiology·2018

Same author

Autoregulation of SafA Assembly through Recruitment of a Protein Cross-Linking Enzyme.

Journal of bacteriology·2018

Same author

Dual-specificity anti-sigma factor reinforces control of cell-type specific gene expression in Bacillus subtilis.

PLoS genetics·2015

Same author

A conserved cysteine residue of Bacillus subtilis SpoIIIJ is important for endospore development.

PloS one·2014

Search research articles

Related Experiment Video

Updated: Jul 20, 2026

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

Sigma X induces competence gene expression in Streptococcus pyogenes.

Robyn L Woodbury¹, Xin Wang, Charles P Moran

¹Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA.

Research in Microbiology

|September 12, 2006

Summary

Streptococcus pyogenes possesses DNA uptake machinery. Sigma X (σX) factor activates competence genes, suggesting this pathogen may develop genetic transformation capabilities.

More Related Videos

Genome-wide Gene Deletions in Streptococcus sanguinis by High Throughput PCR

Genome-wide Gene Deletions in Streptococcus sanguinis by High Throughput PCR

Published on: November 23, 2012

Visual and Microscopic Evaluation of Streptomyces Developmental Mutants

Visual and Microscopic Evaluation of Streptomyces Developmental Mutants

Published on: September 12, 2018

Related Experiment Videos

Last Updated: Jul 20, 2026

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

Genome-wide Gene Deletions in Streptococcus sanguinis by High Throughput PCR

Genome-wide Gene Deletions in Streptococcus sanguinis by High Throughput PCR

Published on: November 23, 2012

Visual and Microscopic Evaluation of Streptomyces Developmental Mutants

Visual and Microscopic Evaluation of Streptomyces Developmental Mutants

Published on: September 12, 2018

Area of Science:

Microbiology
Molecular Biology
Genetics

Background:

Streptococcus pyogenes, a human pathogen, was not previously known to be competent for DNA uptake.
The bacterium harbors genes for DNA uptake and recombination, with promoters containing a conserved CIN-box sequence.
This CIN-box is recognized by the alternative RNA polymerase sigma factor X (σX).

Purpose of the Study:

To investigate the role of sigma X (σX) in regulating competence genes in Streptococcus pyogenes.
To determine if σX can induce the expression of DNA uptake and recombination machinery.
To explore the potential for genetic transformation in S. pyogenes.

Main Methods:

Microarray analysis to assess global gene expression changes induced by σX.
Real-time RT-PCR to quantify the induction levels of specific competence-related transcripts.
In vitro transcription assays using purified RNA polymerase containing σX.

Main Results:

Microarray data revealed that σX significantly induces the expression of competence genes in S. pyogenes.
Real-time RT-PCR confirmed 2-265-fold induction of these transcripts by σX.
The gene femB, an ortholog of a Staphylococcus aureus virulence factor, was directly transcribed in vitro by σX-containing RNA polymerase, confirming σX activation of a CIN-box gene.

Conclusions:

Sigma X (σX) directly activates the expression of competence genes in Streptococcus pyogenes.
The induction of competence machinery by σX suggests that S. pyogenes strains may be capable of natural genetic transformation.
This finding has implications for understanding the evolution and pathogenicity of this important human pathogen.