Related Experiment Video
Updated: Apr 7, 2026
12:24
DNA-affinity-purified Chip DAP-chip Method to Determine Gene Targets for Bacterial Two component Regulatory Systems
Published on: July 21, 2014
17.4K
Bacterial Sigma Factors and Anti-Sigma Factors: Structure, Function and Distribution
1School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK. m.paget@sussex.ac.uk.
Biomolecules
|July 2, 2015
Summary
Sigma factors regulate bacterial gene transcription initiation by binding to RNA polymerase. This review explores sigma-70 class factors and their release from anti-sigma factors via proteolysis, partner-switching, or direct sensing.
Area of Science:
- Bacterial molecular biology
- Gene transcription regulation
Background:
- Sigma factors are essential subunits of bacterial RNA polymerase (RNAP).
- They direct transcription initiation, promoter recognition, and RNA synthesis.
- The sigma-70 class includes housekeeping and alternative sigma factors controlling growth and adaptive responses.
Purpose of the Study:
- To review the structure and function of the sigma-70 class of bacterial sigma factors.
- To elucidate mechanisms of sigma factor control, particularly their sequestration and release.
Main Methods:
- Literature review focusing on sigma factor structure, function, and regulation.
- Analysis of anti-sigma factor interactions and sigma factor release mechanisms.
Main Results:
- Sigma factors are controlled by anti-sigma factors that inhibit RNAP binding.
- Sigma factor release involves diverse mechanisms, often integrating multiple signals.
- Three primary release strategies are: regulated proteolysis, partner-switching, and direct sensing.
Conclusions:
- Sigma factor regulation is crucial for bacterial adaptive responses and growth.
- Understanding these mechanisms provides insights into bacterial gene expression control.
Related Concept Videos
00:43Bacterial RNA Polymerase
33.8K
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
33.8K
01:28Global Regulatory Systems
913
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...
913
01:30Other Stress Responses in Bacteria
533
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...
533
01:29Translational Regulation
848
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...
848
01:29Coordination of Gene Expression Processes in Bacteria
1.0K
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...
1.0K
01:30Bacterial Signaling
43.3K
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...
43.3K