The Aspergillus nidulans homoaconitase gene lysF is negatively regulated by the multimeric CCAAT-binding complex AnCF and positively regulated by GATA sites.
In beta-lactam-antibiotic-producing fungi, such as Aspergillus (Emericella) nidulans, L-alpha-aminoadipic acid is the branching point of the lysine and penicillin biosynthesis pathways. To obtain a deeper insight into the regulation of lysine biosynthesis genes, the regulation of the A. nidulans lysF gene, which encodes homoaconitase, was studied. Band-shift assays indicated that the A. nidulans multimeric CCAAT-binding complex AnCF binds to two of four CCAAT motifs present in the lysF promoter region. AnCF consists at least of three different subunits, designated HapB, HapC, and HapE. In both a delta hapB and a delta hapC strain, the expression of a translational lysF-lacZ gene fusion integrated in single copy at the chromosomal argB gene locus was two to three-fold higher than in a wild-type strain. These data show that AnCF negatively regulates lysF expression. The results of Northern blot analysis and lysF-lacZ expression analysis did not indicate a lysine-dependent repression of lysF expression. Furthermore, mutational analysis of the lysF promoter region revealed that two GATA sites matching the GATA consensus sequence HGATAR positively affected lysF-lacZ expression. Results of Northern blot analysis also excluded that the global nitrogen regulator AreA is the responsible trans-acting GATA-binding factor.
Weidner
G
G
Institut für Mikrobiologie und Genetik, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
Steidl
S
S
Brakhage
A A
AA
D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D023081:CCAAT-Binding Factor / Q000378:metabolism*; D016384:Consensus Sequence; D005656:Fungal Proteins / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D006836:Hydro-Lyases / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
C406362:AnCF protein, Aspergillus nidulans; C079728:AreA protein, Aspergillus nidulans; D023081:CCAAT-Binding Factor; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D006836:Hydro-Lyases; C107855:homoaconitate hydratase