Cloning and Characterization of anAspergillus nidulans Gene Involved in the Regulation of Penicillin Biosynthesis

摘要

To identify regulators of penicillin biosynthesis, a previously isolated mutant of Aspergillus nidulans (Prg-1) which carried the trans-acting prgA1 mutation was used. This mutant also contained fusions of the penicillin biosynthesis genes acvA and ipnA with reporter genes (acvA-uidA andipnA-lacZ) integrated in a double-copy arrangement at the chromosomal argB gene. TheprgA1 mutant strain exhibited only 20 to 50% of theipnA-lacZ and acvA-uidAexpression exhibited by the wild-type strain and had only 20 to 30% of the penicillin produced by the wild-type strain. Here, using complementation with a genomic cosmid library, we isolated a gene (suAprgA1) which complemented the prgA1phenotype to the wild-type phenotype; i.e., the levels of expression of both gene fusions and penicillin production were nearly wild-type levels. Analysis of the suAprgA1 gene in theprgA1 mutant did not reveal any mutation in thesuAprgA1 gene or unusual transcription of the gene. This suggested that the suAprgA1 gene is a suppressor of theprgA1 mutation. The suAprgA1 gene is 1,245 bp long. Its five exons encode a deduced protein that is 303 amino acids long. The putative SUAPRGA1 protein was similar to both the human p32 protein and Mam33p of Saccharomyces cerevisiae. Analysis of the ordered gene library of A. nidulans indicated thatsuAprgA1 is located on chromosome VI. Deletion of thesuAprgA1 gene resulted in an approximately 50% reduction in ipnA-lacZ expression and in a slight reduction in acvA-uidA expression. The ΔsuAprgA1 strain produced about 60% of the amount of penicillin produced by the wild-type strain.