The myb-homologous P gene controls phlobaphene pigmentation in maize floral organs by directly activating a flavonoid biosynthetic gene subset

Cell. 1994 Feb 11;76(3):543-53. doi: 10.1016/0092-8674(94)90117-1.


The maize P gene, which specifies red pigmentation of the kernel pericarp, cob, and other floral organs, has been an important model since the early days of modern genetics. Here we show that P encodes a Myb homolog that recognizes the sequence CCT/AACC, in sharp contrast with the C/TAACGG bound by vertebrate Myb proteins. P binds to and activates transcription of the A1 gene required for 3-deoxy flavonoid and phlobaphene biosynthesis, but not the Bz1 gene required for anthocyanin biosynthesis. The maize C1 gene, which also encodes a Myb homolog, activates both the A1 and Bz1 genes, but only in the presence of a basic-helix-loop-helix coactivator encoded by the maize genes R or B. These results indicate that Myb homologs can differentially regulate gene expression by binding different DNA sequences, through combinatorial interactions with other factors, or both.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Binding Sites
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Flavonoids / biosynthesis*
  • Gene Expression Regulation
  • Genes, Plant*
  • Genes, Regulator*
  • Molecular Sequence Data
  • Mutagenesis
  • Oncogene Proteins v-myb
  • Oncogenes*
  • Pigments, Biological / biosynthesis
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Promoter Regions, Genetic
  • Retroviridae Proteins, Oncogenic / biosynthesis
  • Retroviridae Proteins, Oncogenic / genetics
  • Sequence Homology, Nucleic Acid
  • Transcription, Genetic
  • Vertebrates
  • Zea mays / genetics*
  • Zea mays / physiology


  • DNA-Binding Proteins
  • Flavonoids
  • Oncogene Proteins v-myb
  • P protein, Zea mays
  • Pigments, Biological
  • Plant Proteins
  • Retroviridae Proteins, Oncogenic