PcMYB1, a novel plant protein containing a DNA-binding domain with one MYB repeat, interacts in vivo with a light-regulatory promoter unit

Plant J. 1997 May;11(5):1079-93. doi: 10.1046/j.1365-313x.1997.11051079.x.


Light regulatory unit 1 (LRU1) is necessary for and sufficient to mediate light-dependent activation of the chalcone synthase (CHS) minimal promoter in Petroselinum crispum. This composite promoter unit consists of at least two distinct cis-acting elements, designated ACECHS and MRECHS, both of which are required for light induction. The ACGT-containing element ACECHS interacts with common plant regulatory factors (CPRFs) which belong to the basic region/leucine zipper (bZIP) class of transcription factors. Here, we demonstrate that MRECHS, originally identified as an in vivo DNA footprint, is a MYB recognition element. This element possesses a functional core that is essential for light responsiveness and is specifically recognized by two distantly related MYB-like proteins: MYB305 and the novel factor MYB1 from P. crispum. PcMYB1 was identified by both its specific binding to MRECHS in vitro and recognition of MRECHS in vivo. The deduced amino acid sequence revealed that PcMYB1 contains only one MYB-like repeat. This portion of the protein constitutes the DNA-binding domain. Mutational analysis of PcMYB1 in combination with sequence comparison suggests the presence of a helix-turn-helix structure containing a recognition helix that is sufficient for sequence-specific binding. The structure of this distinct MYB-like DNA-binding domain appears to be conserved in proteins from all three eukaryotic phyla.

Publication types

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

MeSH terms

  • Acyltransferases / genetics*
  • Amino Acid Sequence
  • Binding Sites
  • DNA Footprinting
  • DNA Mutational Analysis
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Plant
  • Light
  • Molecular Sequence Data
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Promoter Regions, Genetic*
  • Protein Binding
  • Protein Structure, Secondary
  • Proto-Oncogene Proteins c-myb*
  • Repetitive Sequences, Nucleic Acid
  • Sequence Homology, Amino Acid
  • Tissue Distribution
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Vegetables / genetics*
  • Vegetables / radiation effects


  • DNA-Binding Proteins
  • MYB1 protein, Petroselinum crispum
  • Plant Proteins
  • Proto-Oncogene Proteins c-myb
  • Transcription Factors
  • Acyltransferases
  • flavanone synthetase

Associated data

  • GENBANK/U67132
  • GENBANK/U67133
  • GENBANK/U67134