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Pc MYB1, a novel plant protein containing a DNA‐binding domain with one MYB repeat, interacts in vivo with a light‐regulatory promoter unit
Author(s) -
Feldbrügge Michael,
Sprenger Markus,
Hahlbrock Klaus,
Weisshaar Bernd
Publication year - 1997
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1997.11051079.x
Subject(s) - leucine zipper , bzip domain , myb , transcription factor , biology , dna binding protein , dna , promoter , transcription (linguistics) , chalcone synthase , binding site , dna binding domain , microbiology and biotechnology , genetics , biochemistry , gene , gene expression , linguistics , philosophy
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 ACE CHS and MRE CHS , both of which are required for light induction. The ACGT‐containing element ACE CHS interacts with common plant regulatory factors (CPRFs) which belong to the basic region/leucine zipper (bZIP) class of transcription factors. Here, we demonstrate that MRE CHS , 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 . Pc MYB1 was identified by both its specific binding to MRE CHS in vitro and recognition of MRE CHS in vivo . The deduced amino acid sequence revealed that Pc MYB1 contains only one MYB‐like repeat. This portion of the protein constitutes the DNA‐binding domain. Mutational analysis of Pc MYB1 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.