A promiscuous intermediate underlies the evolution of LEAFY DNA binding specificity

Science. 2014 Feb 7;343(6171):645-8. doi: 10.1126/science.1248229. Epub 2014 Jan 16.


Transcription factors (TFs) are key players in evolution. Changes affecting their function can yield novel life forms but may also have deleterious effects. Consequently, gene duplication events that release one gene copy from selective pressure are thought to be the common mechanism by which TFs acquire new activities. Here, we show that LEAFY, a major regulator of flower development and cell division in land plants, underwent changes to its DNA binding specificity, even though plant genomes generally contain a single copy of the LEAFY gene. We examined how these changes occurred at the structural level and identify an intermediate LEAFY form in hornworts that appears to adopt all different specificities. This promiscuous intermediate could have smoothed the evolutionary transitions, thereby allowing LEAFY to evolve new binding specificities while remaining a single-copy gene.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / classification
  • Arabidopsis Proteins / genetics
  • DNA, Plant / chemistry*
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / classification
  • DNA-Binding Proteins / genetics*
  • Electrophoretic Mobility Shift Assay
  • Evolution, Molecular*
  • Gene Dosage
  • Molecular Sequence Data
  • Mutation
  • Phylogeny
  • Plant Proteins / chemistry*
  • Plant Proteins / classification
  • Plant Proteins / genetics*
  • Protein Binding / genetics
  • Protein Structure, Tertiary
  • Species Specificity
  • Transcription Factors / chemistry
  • Transcription Factors / classification
  • Transcription Factors / genetics


  • Arabidopsis Proteins
  • DNA, Plant
  • DNA-Binding Proteins
  • LFY protein, Arabidopsis
  • Plant Proteins
  • Transcription Factors

Associated data

  • GENBANK/KF193872
  • GENBANK/KF269532
  • GENBANK/KF269533
  • GENBANK/KF269534
  • GENBANK/KF269535
  • GENBANK/KF269536
  • PDB/4BHK