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Polyketide synthase gene pksM from Aspergillus terreus expressed during growth phase
S Pazoutová1, M Linka, S Storková
1Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Abstract:
The polyketide synthase gene pksM was detected in the genomic DNA library of Aspergillus terreus by hybridization with the 6-methylsalicylic acid synthase (6-MSAS) gene of Penicillium patulum as a probe. 9524 bp of the cloned DNA were sequenced and a 5.5 kb open reading frame was revealed. A single intron (62 bp) was identified in the conserved position. Two transcription start points were determined within the 5'-flanking region at 50 and 72 (major) bp upstream from the putative translation initiation codon ATG. The conserved active site motifs for ketosynthase, acyltransferase, dehydratase, ketoreductase and acyl carrier protein were found within the predicted polypeptide consisting of 1803 amino acids. Unlike the P. patulum 6-MSAS gene, the transcription of pksM from A. terreus was observed in the middle of the vegetative growth phase.
Insights
Researchers identified the polyketide synthase gene (pksM) in Aspergillus terreus. Its DNA sequence and gene structure were analyzed, revealing conserved active site motifs and distinct transcription patterns compared to related fungi.
Area of Science:
- * Molecular Biology
- * Mycology
- * Biochemistry
Background:
- * Polyketide synthases (PKS) are crucial enzymes in secondary metabolite biosynthesis.
- * Aspergillus terreus is a fungus with industrial and medical significance.
- * Understanding PKS gene regulation provides insights into fungal metabolism.
Purpose of the Study:
- * To clone and characterize the pksM gene from Aspergillus terreus.
- * To elucidate the structural and regulatory features of the pksM gene.
- * To compare the pksM gene with its homolog in Penicillium patulum.
Main Methods:
- * DNA hybridization using the 6-methylsalicylic acid synthase (6-MSAS) gene as a probe.
- * DNA sequencing of the cloned pksM gene and its flanking regions.
- * Identification of open reading frames, introns, and transcription start points.
- * Analysis of conserved active site motifs in the predicted polypeptide.
Main Results:
- * The pksM gene was successfully detected and cloned from Aspergillus terreus.
- * A 5.5 kb open reading frame encoding a 1803 amino acid polypeptide was identified.
- * Conserved active site motifs for PKS enzymes were found.
- * Two transcription start points were determined, and transcription occurred during the vegetative growth phase.
Conclusions:
- * The characterized pksM gene encodes a functional polyketide synthase in Aspergillus terreus.
- * The gene structure and regulatory elements are conserved, with notable differences in transcription timing compared to Penicillium patulum.
- * This study contributes to the understanding of secondary metabolite production in Aspergillus species.