Pho4 is a basic helix-loop-helix (bHLH) transcription factor found in S. cerevisiae and other yeasts.[2]

The Pho4 homodimer binds to DNA sequences containing the bHLH binding site 5'-CACGTG-3'.[3] This sequence is found in the promoters of genes upregulated in response to phosphate availability such as the PHO5 gene.[4]


  1. ^ PDB: 1a0a​; Shimizu T, Toumoto A, Ihara K, Shimizu M, Kyogoku Y, Ogawa N, Oshima Y, Hakoshima T (August 1997). "Crystal structure of PHO4 bHLH domain-DNA complex: flanking base recognition". EMBO J. 16 (15): 4689–97. doi:10.1093/emboj/16.15.4689. PMC 1170095Freely accessible. PMID 9303313. 
  2. ^ Berben G, Legrain M, Gilliquet V, Hilger F (1990). "The yeast regulatory gene PHO4 encodes a helix-loop-helix motif". Yeast. 6 (5): 451–4. doi:10.1002/yea.320060510. PMID 2220078. 
  3. ^ Shao D, Creasy CL, Bergman LW (February 1998). "A cysteine residue in helixII of the bHLH domain is essential for homodimerization of the yeast transcription factor Pho4p". Nucleic Acids Res. 26 (3): 710–4. doi:10.1093/nar/26.3.710. PMC 147311Freely accessible. PMID 9443961. 
  4. ^ Ogawa N, Oshima Y (May 1990). "Functional domains of a positive regulatory protein, PHO4, for transcriptional control of the phosphatase regulon in Saccharomyces cerevisiae". Mol. Cell. Biol. 10 (5): 2224–36. PMC 360570Freely accessible. PMID 2183025. 

External links