Single-stranded DNA binding factor AtWHY1 modulates telomere length homeostasis in Arabidopsis

Plant J. 2007 Feb;49(3):442-51. doi: 10.1111/j.1365-313X.2006.02974.x. Epub 2007 Jan 1.


Telomere homeostasis, a process that is essential for the maintenance of chromosome integrity, is regulated by telomerase and a collection of associated proteins. By mass spectrometry we have identified a new telomeric protein encoded by the AtWHY1 (Arabidopsis thaliana Whirly 1) gene in Arabidopsis. AtWHY1 specifically binds the single-stranded plant telomeric DNA sequences, but not double-stranded telomeric DNA. To gain insights into the function of AtWHY1 in telomere biogenesis, we have identified two Arabidopsis lines harboring T-DNA insertions in AtWHY1. These lines exhibit neither growth nor developmental defects. However, AtWHY1-deficient plants show a steady increase in the length of telomere tracts over generations. This telomere elongation is correlated with a significant increase in telomerase activity. On the contrary, transgenic plants expressing AtWHY1 show a decreased telomerase activity and shortened telomeres. The evidence presented here indicates that AtWHY1 is a new family of telomere end-binding proteins that plays a role in regulating telomere-length homeostasis in Arabidopsis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Binding Sites
  • Chromosomes, Plant / metabolism
  • DNA, Bacterial
  • DNA, Single-Stranded / metabolism*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Expression
  • Homeostasis / physiology
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Plants, Genetically Modified / metabolism
  • Sequence Homology, Amino Acid
  • Solanum tuberosum / chemistry
  • Telomerase / antagonists & inhibitors
  • Telomerase / metabolism
  • Telomere / metabolism*
  • Telomere-Binding Proteins / metabolism*


  • Arabidopsis Proteins
  • DNA, Bacterial
  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • T-DNA
  • Telomere-Binding Proteins
  • Whirly1 protein, Arabidopsis
  • Telomerase