Related Experiment Video
Updated: Jul 27, 2026
08:29
Using Coculture to Detect Chemically Mediated Interspecies Interactions
Published on: November 1, 2013
Transition-state regulators: sentinels of Bacillus subtilis post-exponential gene expression
1Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California 92037.
Molecular Microbiology
|February 1, 1993
Summary
Bacillus subtilis uses transition-state regulators to control gene expression during nutrient depletion. These proteins, like AbrB, Hpr, and Sin, manage essential stationary-phase functions and sporulation timing.
Area of Science:
- Microbiology
- Molecular Biology
- Gene Regulation
Background:
- Bacillus subtilis activates alternative metabolic and energy production pathways when nutrients are scarce.
- Gene expression changes significantly during the transition from active growth to stationary phase.
- Transition-state regulators control gene expression during this critical growth phase.
Purpose of the Study:
- To investigate the role of transition-state regulators in Bacillus subtilis.
- To understand how these regulators control gene expression in response to nutrient depletion.
- To elucidate the involvement of regulators like AbrB, Hpr, and Sin in stationary-phase phenomena and sporulation.
Main Methods:
- Analysis of gene expression patterns in Bacillus subtilis under nutrient-depleted conditions.
- Identification and characterization of key transition-state regulatory proteins (AbrB, Hpr, Sin).
- Investigating the regulatory networks and target genes controlled by these proteins.
Main Results:
- Transition-state regulators are crucial for managing gene expression during the growth-to-stationary phase transition.
- These regulators exhibit redundant control over specific genes and pleiotropic effects across various pathways.
- AbrB, Hpr, and Sin proteins prevent the expression of unnecessary genes during exponential growth.
Conclusions:
- Transition-state regulators integrate cellular processes, including sporulation, with stationary-phase adaptation.
- These regulators fine-tune gene expression magnitude based on environmental cues.
- Understanding these regulatory mechanisms is key to comprehending Bacillus subtilis survival strategies.
More Related Videos
10:18A Fast and Reliable Pipeline for Bacterial Transcriptome Analysis Case study: Serine-dependent Gene Regulation in Streptococcus pneumoniae
Published on: April 25, 2015
07:28Live Cell Fluorescence Microscopy to Observe Essential Processes During Microbial Cell Growth
Published on: November 24, 2017
Related Concept Videos
01:27Constitutive and Regulated Gene Expression
Gene expression in prokaryotes is governed by constitutive and regulated systems, allowing cells to balance the production of essential proteins with adaptive responses to environmental changes.Constitutive Gene ExpressionConstitutive, or housekeeping, genes are continuously expressed as they encode proteins vital for fundamental cellular processes. These include enzymes for glycolysis, ribosomal components for protein synthesis, and proteins involved in DNA replication. Their constant...
01:23Transcriptional Regulation: Riboswitches
Riboswitches are RNA elements that regulate gene expression by altering their secondary structures in response to specific effector molecules. These elements, located in the leader regions of certain mRNAs, act as transcriptional regulators by toggling between alternative conformations to control downstream gene expression. Riboswitch-mediated regulation is a precise mechanism for modulating biosynthetic pathways, as exemplified by the riboflavin biosynthesis pathway in Bacillus...
01:28Global 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...
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...
01:23Stringent 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...