Related Experiment Video
Updated: May 9, 2026
12:23
Recombinant Protein Expression, Crystallization, and Biophysical Studies of a Bacillus-conserved Nucleotide Pyrophosphorylase, BcMazG
Published on: May 16, 2017
Transcriptomic and phenotypic analysis of paralogous spx gene function in Bacillus anthracis Sterne
Skye Barendt1, Hyunwoo Lee, Cierra Birch
1Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health and Science University, Beaverton, Oregon.
Microbiologyopen
|July 23, 2013
Summary
Bacillus anthracis Sterne
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Spx proteins are redox-sensitive regulators crucial for thiol homeostasis in Bacillus subtilis.
- Spx orthologs are conserved in low %GC Gram-positive bacteria, often appearing as multiple paralogs.
- Bacillus anthracis Sterne possesses two paralogous spx genes: spxA1 and spxA2.
Purpose of the Study:
- To investigate the phenotypes of spx null mutations in Bacillus anthracis Sterne.
- To identify specific genes regulated by each Spx paralog (SpxA1 and SpxA2).
- To understand the role of Spx paralogs in responding to disulfide stress and pathogenesis.
Main Methods:
- Phenotypic analysis of spx null mutants under oxidative stress conditions (diamide, hydrogen peroxide).
- Gene expression profiling using microarray and quantitative real-time polymerase chain reaction (RT-qPCR).
- Analysis of strains expressing protease-resistant SpxA1DD and SpxA2DD alleles.
Main Results:
- spxA1 null mutants showed sensitivity to diamide and hydrogen peroxide.
- The spxA1 spxA2 double mutant exhibited hypersensitivity to diamide.
- Microarray and RT-qPCR revealed distinct regulons controlled by SpxA1 and SpxA2, including genes involved in thiol homeostasis, oxidative stress response, and pathogenesis.
- A regulatory link between spxA1 and spxA2 was identified.
Conclusions:
- SpxA1 and SpxA2 are key transcriptional regulators involved in relieving disulfide stress in Bacillus anthracis.
- Each Spx paralog governs a unique set of genes, contributing to cellular processes beyond stress response.
- The identified Spx-regulated genes have implications for Bacillus anthracis pathogenesis.
Related Concept Videos
01:17Gene 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...
01:29Coordination of Gene Expression Processes in Bacteria
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
01:23Stringent Response in E. coli
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
01:28Regulation 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...
01:30Other Stress Responses in Bacteria
Bacteria have global regulatory systems that control several types of stress mechanisms. These include Pho regulon and the heat shock response, which are essential systems for environmental adaptation, such as nutrient limitation and proteotoxic stress. The Pho regulon and the heat shock response exemplify bacterial resilience, enabling rapid adaptation to fluctuating environmental conditions.Pho RegulonBacteria require phosphorus for essential cellular processes, including nucleic acid...