The C. elegans maternal-effect gene clk-2 is essential for embryonic development, encodes a protein homologous to yeast Tel2p and affects telomere length

Development. 2001 Oct;128(20):4045-55. doi: 10.1242/dev.128.20.4045.


The Caenorhabditis elegans maternal-effect clk genes are involved in the temporal control of development and behavior. We report the genetic and molecular characterization of clk-2. A temperature-sensitive mutation in the gene clk-2 affects embryonic and post-embryonic development, reproduction, and rhythmic behaviors. Yet, virtually all phenotypes are fully maternally rescued. Embryonic development strictly requires the activity of maternal clk-2 during a narrow time window between oocyte maturation and the two- to four-cell embryonic stage. Positional cloning of clk-2 reveals that it encodes a protein homologous to S. cerevisiae Tel2p. In yeast, the gene TEL2 regulates telomere length and participates in gene silencing at subtelomeric regions. In C. elegans, clk-2 mutants have elongated telomeres, and clk-2 overexpression can lead to telomere shortening. Tel2p has been reported to bind to telomeric DNA repeats in vitro. However, we find that a functional CLK-2::GFP fusion protein is cytoplasmic in worms. We discuss how the phenotype of clk-2 mutants could be the result of altered patterns of gene expression.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans Proteins / genetics*
  • DNA, Helminth / genetics
  • Disorders of Sex Development / genetics
  • Female
  • Fungal Proteins / genetics
  • Gene Expression Regulation, Developmental
  • Genes, Helminth*
  • Helminth Proteins / genetics*
  • Molecular Sequence Data
  • Mutation
  • Phenotype
  • Saccharomyces cerevisiae / genetics
  • Sequence Homology, Amino Acid
  • Telomere / genetics
  • Telomere-Binding Proteins*
  • Temperature


  • Caenorhabditis elegans Proteins
  • DNA, Helminth
  • Fungal Proteins
  • Helminth Proteins
  • Telomere-Binding Proteins
  • clk-2 protein, C elegans