Abstract
A yeast genetic system was developed to study how the basic regions of basic-helix-loop-helix (bHLH) proteins distinguish between related consensus bHLH binding sites, with nucleotide sequence CANNTG. The yeast bHLH protein CBF1 binds to the sequence CAC(A/G)TG found in the yeast centromere element CDE1 and in promoter regions of several yeast genes involved in methionine biosynthesis. Using a functional assay to rescue a mutant cbf1 yeast strain from methionine auxotrophy, we determined that the basic region of CBF1 could be replaced by the homologous region of either the vertebrate USF transcription factor or c-Myc, both of which bind CACGTG. The homologous region of the AP4 transcription factor, which recognizes the sequence CAGCTG, could not functionally replace the CBF1 basic region. However, only a single substitution, Met----Arg, in the AP4 basic region of the inactive chimera CBF-AP4 was sufficient to restore CBF1 function. In randomization experiments, only arginine or lysine provided functional substitutions at the AP4 methionine position. The results suggest that this conserved arginine residue in the basic regions of Myc-related bHLH proteins discriminates between CAC(A/G)TG and related sites.
Keywords
Affiliated Institutions
Related Publications
Cloning of the Ah-receptor cDNA reveals a distinctive ligand-activated transcription factor.
A cDNA encoding the murine Ah receptor (Ahb-1 allele for aromatic hydrocarbon responsiveness) has been isolated and characterized. Analysis of the deduced protein sequence revea...
Characterization of a Subset of the Basic-Helix-Loop-Helix-PAS Superfamily That Interacts with Components of the Dioxin Signaling Pathway
In an effort to better understand the mechanism of toxicity of 2,3,7, 8-tetrachlorodibenzo-p-dioxin, we employed an iterative search of human expressed sequence tags to identify...
Domains Required for Dimerization of Yeast Rad6 Ubiquitin-Conjugating Enzyme and Rad18 DNA Binding Protein
The RAD6 gene of Saccharomyces cerevisiae encodes a ubiquitin-conjugating enzyme required for postreplicational repair of UV-damaged DNA and for damage-induced mutagenesis. In a...
A novel bHLH-PAS factor with close sequence similarity to hypoxia-inducible factor 1α regulates the <i>VEGF</i> expression and is potentially involved in lung and vascular development
We have isolated and characterized a cDNA for a novel Per-Arnt/AhR-Sim basic helix–loop–helix (bHLH-PAS) factor that interacts with the Ah receptor nuclear translocator (Arnt), ...
Molecular evolution of the MyoD family of transcription factors.
Myogenesis in skeletal muscle is a cascade of developmental events whose initiation involves the MyoD family of transcription factors. Evolutionary analyses of amino acid sequen...
Publication Info
- Year
- 1992
- Type
- article
- Volume
- 89
- Issue
- 2
- Pages
- 599-602
- Citations
- 170
- Access
- Closed
External Links
Social Impact
Social media, news, blog, policy document mentions
Citation Metrics
Cite This
Identifiers
- DOI
- 10.1073/pnas.89.2.599