The Aspergillus PacC zinc finger transcription factor mediates regulation of both acid- and alkaline-expressed genes by ambient pH.
The pH regulation of gene expression in Aspergillus nidulans is mediated by pacC, whose 678 residue-derived protein contains three putative Cys2His2 zinc fingers. Ten pacCc mutations mimicking growth at alkaline pH remove between 100 and 214 C-terminal residues, including a highly acidic region containing an acidic glutamine repeat. Nine pacC+/- mutations mimicking acidic growth conditions remove between 299 and 505 C-terminal residues. Deletion of the entire pacC coding region mimics acidity but leads additionally to poor growth and conidiation. A PacC fusion protein binds DNA with the core consensus GCCARG. At alkaline ambient pH, PacC activates transcription of alkaline-expressed genes (including pacC itself) and represses transcription of acid-expressed genes. pacCc mutations obviate the need for pH signal transduction.
Tilburn
J
J
Department of Infectious Diseases and Bacteriology, Royal Postgraduate Medical School, London, UK.
Sarkar
S
S
Widdick
D A
DA
Espeso
E A
EA
Orejas
M
M
Mungroo
J
J
Peñalva
M A
MA
Arst
H N
HN
D000136:Acid-Base Equilibrium; D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004843:Epistasis, Genetic; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000502:physiology*; D016335:Zinc Fingers
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C092394:PacC protein, Aspergillus; D012333:RNA, Messenger; D014157:Transcription Factors