Molecular evolution of VEF-domain-containing PcG genes in plants

Mol Plant. 2009 Jul;2(4):738-754. doi: 10.1093/mp/ssp032. Epub 2009 Jun 19.

Abstract

Arabidopsis VERNALIZATION2 (VRN2), EMBRYONIC FLOWER2 (EMF2), and FERTILIZATION-INDEPENDENT SEED2 (FIS2) are involved in vernalization-mediated flowering, vegetative development, and seed development, respectively. Together with Arabidopsis VEF-L36, they share a VEF domain that is conserved in plants and animals. To investigate the evolution of VEF-domain-containing genes (VEF genes), we analyzed sequences related to VEF genes across land plants. To date, 24 full-length sequences from 11 angiosperm families and 54 partial sequences from another nine families were identified. The majority of the full-length sequences identified share greatest sequence similarity with and possess the same major domain structure as Arabidopsis EMF2. EMF2-like sequences are not only widespread among angiosperms, but are also found in genomic sequences of gymnosperms, lycophyte, and moss. No FIS2- or VEF-L36-like sequences were recovered from plants other than Arabidopsis, including from rice and poplar for which whole genomes have been sequenced. Phylogenetic analysis of the full-length sequences showed a high degree of amino acid sequence conservation in EMF2 homologs of closely related taxa. VRN2 homologs are recovered as a clade nested within the larger EMF2 clade. FIS2 and VEF-L36 are recovered in the VRN2 clade. VRN2 clade may have evolved from an EMF2 duplication event that occurred in the rosids prior to the divergence of the eurosid I and eurosid II lineages. We propose that dynamic changes in genome evolution contribute to the generation of the family of VEF-domain-containing genes. Phylogenetic analysis of the VEF domain alone showed that VEF sequences continue to evolve following EMF2/VRN2 divergence in accordance with species relationship. Existence of EMF2-like sequences in animals and across land plants suggests that a prototype form of EMF2 was present prior to the divergence of the plant and animal lineages. A proposed sequence of events, based on domain organization and occurrence of intermediate sequences throughout angiosperms, could explain VRN2 evolution from an EMF2-like ancestral sequence, possibly following duplication of the ancestral EMF2. Available data further suggest that VEF-L36 and FIS2 were derived from a VRN2-like ancestral sequence. Thus, the presence of VEF-L36 and FIS2 in a genome may ultimately be dependent upon the presence of a VRN2-like sequence.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / classification
  • Arabidopsis Proteins / genetics
  • Carrier Proteins / chemistry
  • Carrier Proteins / classification
  • Carrier Proteins / genetics
  • DNA-Binding Proteins
  • Evolution, Molecular*
  • Models, Genetic
  • Molecular Sequence Data
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / classification
  • Nuclear Proteins / genetics
  • Phylogeny
  • Plant Proteins / chemistry
  • Plant Proteins / classification
  • Plant Proteins / genetics*
  • Protein Structure, Tertiary
  • Repressor Proteins / chemistry
  • Repressor Proteins / classification
  • Repressor Proteins / genetics
  • Sequence Homology, Amino Acid
  • Transcription Factors / chemistry
  • Transcription Factors / classification
  • Transcription Factors / genetics

Substances

  • Arabidopsis Proteins
  • Carrier Proteins
  • DNA-Binding Proteins
  • EMF2 protein, Arabidopsis
  • FIS2 protein, Arabidopsis
  • Nuclear Proteins
  • Plant Proteins
  • Repressor Proteins
  • Transcription Factors
  • VRN2 protein, Arabidopsis

Associated data

  • GENBANK/ABD85300
  • GENBANK/ABD85301
  • GENBANK/ABD98790
  • GENBANK/ABD98791
  • GENBANK/ABI99480
  • GENBANK/ABI99481