Short communication: the N-terminal fragment of Arabidopsis photomorphogenic repressor COP1 maintains partial function and acts in a concentration-dependent manner

Plant J. 1999 Dec;20(6):713-7. doi: 10.1046/j.1365-313x.1999.00639.x.


Arabidopsis seedlings exhibit distinct developmental patterns according to their light environment: photomorphogenesis in the light and etiolation or skotomorphogenesis in darkness. COP1 acts within the nucleus to repress photomorphogenesis in darkness, while light depletes COP1 from nucleus and abrogates this repression. COP1 contains three structural modules: a RING finger followed by a coiled-coil domain, and a WD40 repeat domain at the C-terminus. By introducing various domain deletion mutants of COP1 into cop1 null mutant backgrounds, we show that all three domains are essential for the function of COP1 in vivo. Interestingly, a fragment containing the N-terminal 282 amino acids of COP1 (N282) with both the RING finger and coiled-coil modules is sufficient to rescue the lethality of the cop1 null mutations at low expression level. However, high expression levels of the N282 fragment result in a phenocopy of the cop1 null mutation. The sensitivity of the seedling to levels of N282 could reflect the importance of the abundance of COP1 for the appropriate regulation of photomorphogenic development.

Publication types

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

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins*
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Crosses, Genetic
  • Darkness
  • Genes, Plant
  • Light
  • Morphogenesis / radiation effects
  • Mutation
  • Peptide Fragments / chemistry
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Phenotype
  • Plant Development
  • Plant Proteins / chemistry*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plants / metabolism
  • Plants / radiation effects
  • Protein Structure, Tertiary
  • Repressor Proteins / chemistry*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Ubiquitin-Protein Ligases*


  • Arabidopsis Proteins
  • Carrier Proteins
  • Peptide Fragments
  • Plant Proteins
  • Repressor Proteins
  • AT2G32950 protein, Arabidopsis
  • Ubiquitin-Protein Ligases