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A putative regulatory element for carbon-source-dependent differentiation in Streptomyces griseus
Kenji Ueda1, Kouichi Matsuda1, Hideaki Takano1
1Department of Applied Biological Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-8510, Japan1.
Microbiology (Reading, England)
|October 12, 1999
Summary
Researchers identified a DNA fragment that represses Streptomyces griseus differentiation. This repression is dependent on the carbon source, suggesting a mechanism for initiating development.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Cellular differentiation in Streptomyces griseus is a complex developmental process.
- Understanding the genetic regulation of this process is crucial for controlling development.
Purpose of the Study:
- To identify genes that negatively regulate cellular differentiation in Streptomyces griseus.
- To elucidate the role of specific DNA fragments and promoters in this repression.
Main Methods:
- Cloning of DNA fragments on a high-copy-number plasmid to identify repressors.
- Subcloning to pinpoint the repressive region.
- Reporter gene assays using a thermostable malate dehydrogenase gene to quantify promoter activity.
Main Results:
- A specific 249 bp DNA fragment repressed aerial mycelium and spore formation, dependent on carbon source (glucose/galactose vs. maltose/mannitol).
- The promoter for ORF3 (P(ORF3)) showed high activity on glucose but decreased on maltose.
- High-copy-number plasmids enhanced P(ORF3) activity.
Conclusions:
- Carbon-source-dependent deactivation of P(ORF3) is likely mediated by a transcriptional repressor.
- This mechanism may play a role in initiating cellular differentiation in Streptomyces griseus.