Regulation of flowering time in Arabidopsis by K homology domain proteins

Proc Natl Acad Sci U S A. 2004 Aug 24;101(34):12759-64. doi: 10.1073/pnas.0404552101. Epub 2004 Aug 13.


The transition from vegetative growth to reproductive development in Arabidopsis is regulated by multiple floral induction pathways, including the photoperiodic, the autonomous, the vernalization, and the hormonal pathways. These pathways converge to regulate the expression of a small set of genes critical for floral initiation and different signal transduction pathways can interact to govern the time to flower. One important regulator of floral initiation is the MADS-box transcription factor FLC, which acts as a negative regulator of flowering in response to both endogenous and environmental signals. In this report, we describe a study of the flowering-time gene, FLK [flowering locus K homology (KH) domain] that encodes a putative RNA-binding protein with three KH domains. The flk mutations cause delayed flowering without a significant effect on the photoperiodic or vernalization responses. FLK functions primarily as a repressor of FLC expression, although it also modestly affects expression of genes associated with the photoperiodic pathway. In addition to FLK, the expression of two other KH domain genes are modestly affected by the flk mutation, suggesting a possible involvement of more than one KH domain protein in the regulation of flowering time in Arabidopsis.

Publication types

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

MeSH terms

  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Biological Clocks / physiology
  • Circadian Rhythm / physiology
  • Flowers / physiology*
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant*
  • MADS Domain Proteins / genetics
  • MADS Domain Proteins / metabolism*
  • Mutation
  • Oligonucleotide Array Sequence Analysis
  • Photoperiod
  • Plants, Genetically Modified
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Time Factors


  • Arabidopsis Proteins
  • MADS Domain Proteins
  • Recombinant Fusion Proteins