The Aspergillus niger GCN4 homologue, cpcA, is transcriptionally regulated and encodes an unusual leucine zipper.
The general control transcriptional regulator gene cpcA of Aspergillus niger was cloned by complementation of a Saccharomyces cerevisiae delta 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 approximately 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 approximately 30% overall identity to yeast GCN4p and Neurospora crassa cpc1p. 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.
Wanke
C
C
Institute for Biochemistry, Microbiology, and Genetics, Friedrich Alexander University, Erlangen, Germany.
Eckert
S
S
Albrecht
G
G
van Hartingsveldt
W
W
Punt
P J
PJ
van den Hondel
C A
CA
Braus
G H
GH
D000640:Amitrole / Q000494:pharmacology; D001234:Aspergillus niger / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D015825:Chromosomes, Fungal; D004271:DNA, Fungal; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D007930:Leucine; D016350:Leucine Zippers / Q000235:genetics*; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000235:genetics; D012333:RNA, Messenger; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
D050976:Basic-Leucine Zipper Transcription Factors; C104754:CPCA protein, Aspergillus niger; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D007930:Leucine; D000640:Amitrole