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Does UVB radiation induce SoxS gene expression in Escherichia coli cells?
A A Gomes1, L M B O Asad, I Felzenszwalb
1Departamento de Biofísica e Biometria, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, 20551-030 Rio de Janeiro, RJ, Brazil.
Radiation and Environmental Biophysics
|September 17, 2004
Summary
Ultraviolet radiation (UVB) can activate the soxS gene, a key component of the SoxRS regulon in bacteria. This induction is linked to the RpoS protein and can occur independently of the SoxR protein.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Stress Response
Background:
- The SoxRS regulon is a critical bacterial defense system against oxidative stress, typically induced by agents like menadione and paraquat.
- Understanding the regulation of this pathway is crucial for comprehending bacterial survival mechanisms.
Purpose of the Study:
- To investigate the effect of physical agents, specifically ultraviolet radiation (UVB), on the SoxRS regulon.
- To elucidate the molecular mechanisms underlying UVB-induced soxS gene expression.
Main Methods:
- Exposure of bacterial cells to UVB radiation (312 nm).
- Analysis of soxS gene expression levels.
- Investigation of the role of RpoS and SoxR proteins in the response.
Main Results:
- UVB radiation was found to induce soxS gene expression.
- The induction of soxS by UVB involves the RpoS protein.
- An unexpected, SoxR-independent increase in soxS gene expression was observed in UVB-irradiated cells, potentially mediated by a rpoS-dependent pathway.
Conclusions:
- Physical agents like UVB can trigger the SoxRS regulon, expanding its known induction triggers beyond chemical agents.
- The RpoS protein plays a significant role in the bacterial response to UVB-induced oxidative stress via the soxS gene.
- A novel regulatory pathway for soxS gene expression, dependent on RpoS but not SoxR, has been identified under UVB irradiation.