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The Aspergillus niger GCN4 homologue, cpcA , is transcriptionally regulated and encodes an unusual leucine zipper
Author(s) -
Wanke Christoph,
Eckert Sabine,
Albrecht Gerd,
Van Hartingsveldt Wim,
Punt Peter J.,
Van Den Hondel Cees A.M.J.J.,
Braus Gerhard H.
Publication year - 1997
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1997.1741549.x
Subject(s) - leucine zipper , biology , amino acid , biochemistry , open reading frame , peptide sequence , neurospora crassa , saccharomyces cerevisiae , aspergillus nidulans , gene , microbiology and biotechnology , mutant
The general control transcriptional regulator gene cpcA of Aspergillus niger was cloned by complementation of a Saccharomyces cerevisiae Δ gcn4 mutant strain. The encoded protein conferred resistance to amino acid analogues when expressed in yeast. Disruption of cpcA in A. niger resulted in a strain which is sensitive towards 3‐aminotriazole and fails to respond to amino acid starvation. cpcA encodes a transcript of ≈2400 nucleotides in length that includes a 5′ leader region of 900 nucleotides. The 5′ leader region contains two small open reading frames, suggesting translational control of gene expression. Steady‐state mRNA levels of cpcA increase by a factor of three upon amino acid starvation. The coding region of cpcA is interrupted by a 57 bp intron and the deduced amino acid sequence displays an ≈30% overall identity to yeast GCN4p and Neurospora crassa cpc‐1p. Critical amino acid residues of the transcriptional activation domains of GCN4p are conserved in cpcAp. The basic DNA‐binding domain shows up to 70% amino acid sequence identity to other basic zipper (bZIP)‐type transcriptional activators. cpcAp binds specifically to a GCN4p recognition element in gel retardation experiments. The C‐terminal dimerization domain encodes a leucine zipper with only a single leucine residue.