Related Experiment Video
Updated: Jul 14, 2026
06:45
Monitoring Intraspecies Competition in a Bacterial Cell Population by Cocultivation of Fluorescently Labelled Strains
Published on: January 18, 2014
Noise in gene expression determines cell fate in Bacillus subtilis
Hédia Maamar1, Arjun Raj, David Dubnau
1Public Health Research Institute Center, New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA.
Science (New York, N.Y.)
|June 16, 2007
Summary
Cell-to-cell gene expression variations, or noise, drive transitions to competence in Bacillus subtilis. Reducing this noise decreases competent cells, showing noise
Area of Science:
- Microbiology
- Systems Biology
- Genetics
Background:
- Cellular processes exhibit random gene expression variations (noise) within isogenic populations, potentially influencing state transitions.
- The role of noise in natural biological systems, particularly in regulating gene expression dynamics, remains largely unexplored.
- In Bacillus subtilis, noise in ComK (competence regulatory protein) is hypothesized to drive transitions to the competent state for DNA uptake.
Purpose of the Study:
- To investigate the impact of noise in comK expression on cellular transitions to competence in Bacillus subtilis.
- To determine if experimental manipulation of noise levels affects the frequency of competent cells.
- To elucidate the temporal regulation mechanisms governing stochastic transitions to competence.
Main Methods:
- Quantification and manipulation of noise in comK gene expression in Bacillus subtilis.
- Experimental reduction of comK expression noise.
- Analysis of temporal dynamics of comK transcription and competence transitions.
Main Results:
- Noise in comK expression actively selects for cells transitioning to competence.
- Experimental reduction of comK expression noise significantly decreased the proportion of competent cells.
- Stochastic transitions to competence are temporally restricted by decreased comK transcription.
Conclusions:
- Noise in gene expression plays a crucial role in regulating stochastic cellular state transitions in natural systems.
- The characteristics of noise are subject to evolutionary pressures, optimizing cellular functions like competence.
- Understanding noise dynamics provides insights into the regulation of gene expression and cellular differentiation.
Related Concept Videos
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...
01:17Gene 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...
01:28Gene 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,...
01:30Bacterial Signaling
Bacterial signaling can occur within bacteria (intracellular) or between bacteria (intercellular). At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell density that causes changes in gene expression. Quorum sensing involves both extracellular and intracellular signaling. The signaling cascade starts with a molecule called an autoinducer (AI). Individual bacteria produce AIs that move out of the bacterial cell...
01:58Prokaryotic Transcriptional Activators and Repressors
The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
Transcription of prokaryotic...
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...