C-myc and the yeast transcription factor PHO4 share a common CACGTG-binding motif.
The basic-helix-loop-helix (b-HLH) motif is common to a number of proteins involved in transcriptional regulation and cell-type determination. The b-HLH motif is also present in the S. cerevisiae transcription factor PHO4 which positively regulates the acid phosphatase gene PHO5. In this report we show that the b-HLH region of PHO4 is sufficient to confer specific DNA-binding to the sequence CACGTG and, by comparison of the basic regions of PHO4 with those of other recently isolated CACGTG-binding proteins, we identify a specific subset of conserved amino acids in the basic region likely to confer DNA-binding specificity. On the basis of these observations we predict successfully the effect of substituting the PHO4 basic region with that from c-myc and show that the chimaeric protein activates transcription from the CACGTG elements present in the PHO5 UAS. From these data it is clear that the myc basic region confers specific binding to the sequence CACGTG.
Fisher
F
F
Marie Curie Research Institute, Oxted, Surrey, UK.
Jayaraman
P S
PS
Goding
C R
CR
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D003850:Deoxyribonuclease I; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016271:Proto-Oncogene Proteins c-myc / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000032:analysis; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000187:drug effects
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C060292:PHO4 protein, S cerevisiae; D016271:Proto-Oncogene Proteins c-myc; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004247:DNA; D003850:Deoxyribonuclease I