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Factors affecting DNA-binding proteins and pcbC transcript levels in Penicillium chrysogenum
T Vichitsoonthonkul1, Y W Chu, V Patel
1King Mongkut Institute of Technology, Faculty of Science, Bangkok 10140, Thailand.
Current Genetics
|November 1, 1996
Summary
Penicillium chrysogenum protein-DNA interactions were studied using electromobility shift assays. These interactions, particularly complexes A and B, correlate with pcbC gene expression and are influenced by pH and growth medium.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Penicillium chrysogenum is a key industrial fungus.
- Understanding gene regulation in P. chrysogenum is crucial for optimizing penicillin production.
- The pcbC gene encodes isopenicillin N synthase, a critical enzyme in penicillin biosynthesis.
Purpose of the Study:
- To investigate protein-DNA interactions regulating the pcbC gene in P. chrysogenum.
- To identify specific protein-DNA complexes and their correlation with pcbC transcript levels.
- To explore the influence of environmental factors like pH and medium composition on these interactions.
Main Methods:
- Electromobility shift assays (EMSA) were performed using protein extracts from P. chrysogenum.
- A DNA probe covering the promoter region (-10 to -132) of the pcbC gene was used.
- Protein extracts were obtained from cultures grown in complex and defined media, as well as from spores.
- pcbC transcript levels were quantified using techniques not explicitly stated but implied by 'transcript levels'.
Main Results:
- Four distinct protein-DNA complexes (A-D) were observed with the pcbC promoter region.
- Complexes A and B were consistently detected in liquid cultures and spores.
- Levels of complexes A and B generally correlated with pcbC transcript abundance.
- Extracellular pH and medium composition influenced both complex formation and pcbC transcript levels.
- In defined medium with glucose, pcbC transcript was undetectable in the wild-type strain but present in the high-producing P-2 strain.
- In complex medium, pcbC transcript was detectable during exponential growth for both strains, irrespective of high glucose concentrations.
Conclusions:
- Specific protein-DNA interactions, identified as complexes A and B, are involved in the regulation of the pcbC gene in P. chrysogenum.
- These regulatory mechanisms are sensitive to environmental cues such as pH and nutrient availability.
- Differences in pcbC gene expression between wild-type and high-producing strains (P-2) were observed under specific conditions, highlighting regulatory variations.