Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The isopenicillin N synthetase gene (pcbC) was isolated from a genomic library of Penicillium chrysogenum BC39813, a penicillin production strain. The nucleotide sequence, including 555 bp upstream of the translation start site was determined. Various deletions within the pcbC 5'-region were constructed and linked to the Escherichia coli lacZ gene. An Aspergillus nidulans argB strain was transformed with DNA of these constructions. The region essential for promoter function could be localized between positions -307 and -89 by analyzing beta-galactosidase expression of transformants containing a single copy of the corresponding plasmid integrated at the homologous argB locus. A region responsible for regulatory effects concerning nitrogen metabolism was identified by determining beta-galactosidase activities in cell-lysates of transformants cultivated under varying growth conditions. Two major transcription start sites at positions -131 and -132, as well as a further upstream located site at position -397 +/- 1 could be located by primer extension studies employing RNA isolated from P. chrysogenum BC39813.
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PMID:Molecular characterization and functional analysis in Aspergillus nidulans of the 5'-region of the Penicillium chrysogenum isopenicillin N synthetase gene. 136 95

The Aspergillus nidulans IPNS gene, encoding isopenicillin N synthetase, is a secondary metabolism gene. It is contiguous to, but divergently transcribed from, the ACVS gene at the penicillin gene cluster. The untranslated region between both ORFs is 872bp long. Here we present the physical and functional characterization of the IPNS transcriptional unit. Transcriptional start point (tsp) mapping reveals heterogeneity at the 5'-end of the mRNA, with a major start at -106 relative to the initiation codon. This indicates that the actual length of the non-transcribed intergenic region is 525bp. Functional elements in the IPNS upstream region have been defined by assaying beta-galactosidase activity in extracts from recombinant strains carrying deletion derivatives of the IPNS promoter fused to lacZ, integrated in single copy at the argB locus. Strains were grown in penicillin production broth under carbon catabolite repressing or derepressing conditions. The results of deletion analysis indicate that: (i) the IPNS promoter is mostly regulated by negative controls that act upon a high basal activity; (ii) sequential deletion of three of the negative cis-acting elements results in a mutated promoter that is 40 times (sucrose broth) or 12 times (lactose broth) more active than the wild type; (iii) one of these negative cis-acting elements is involved in sucrose repression. Strikingly, it is located outside the non-transcribed 525bp intergenic region and maps to the coding region of the divergently transcribed ACVS gene; (iv) a 5'-deletion up to -56 (relative to the major tsp) contains information to provide almost half of the maximal promoter activity and allows initiation of transcription at the correct site. By using total-protein extracts from mycelia grown under penicillin producing conditions we have detected a DNA-binding activity that specifically shifts a promoter fragment located between -654 and -455 (relative to IPNS tsp). Deletions covering this region partially abolish IPNS promoter activity. The fragment in question overlaps the ACVS tsp.
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PMID:Molecular characterization of a fungal secondary metabolism promoter: transcription of the Aspergillus nidulans isopenicillin N synthetase gene is modulated by upstream negative elements. 823 16