Analysis of the function of two circadian-regulated CONSTANS-LIKE genes

Plant J. 2001 Apr;26(1):15-22. doi: 10.1046/j.1365-313x.2001.01003.x.


The Arabidopsis genes CONSTANS-LIKE 1 (COL1) and CONSTANS-LIKE 2 (COL2) are predicted to encode zinc finger proteins with approximately 67% amino acid identity to the protein encoded by the flowering-time gene CONSTANS (CO). We show that the circadian clock regulates expression of COL1 and COL2 with a peak in transcript levels around dawn. We analyzed transgenic plants misexpressing COL1, COL2 and CO. Unlike CO, altered expression of COL1 and COL2 in transgenic plants had little effect on flowering time. However, analysis of circadian phenotypes in the transgenic plants showed that over-expression of COL1 can shorten the period of two distinct circadian rhythms. Experiments with the highest COL1 over-expressing line indicate that its circadian defects are fluence rate-dependent, suggesting an effect on a light input pathway(s).

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 / genetics*
  • Arabidopsis / physiology
  • Arabidopsis Proteins*
  • Biological Clocks
  • Blotting, Northern
  • Circadian Rhythm*
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • Luminescent Measurements
  • Phenotype
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • RNA, Messenger / analysis
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Zinc Fingers*


  • Arabidopsis Proteins
  • CONSTANS protein, Arabidopsis
  • DNA-Binding Proteins
  • Plant Proteins
  • RNA, Messenger
  • Transcription Factors