An alternative pathway for yeast telomere maintenance rescues est1- senescence

Cell. 1993 Apr 23;73(2):347-60. doi: 10.1016/0092-8674(93)90234-h.


Yeast cells lacking a functional EST1 gene show progressive shortening of the terminal G1-3T telomeric repeats and a parallel increase in the frequency of cell death. Although the majority of the cells in an est1- culture die, a minor subpopulation survives the potentially lethal consequences of the est1 mutation. We show that these est1- survivors arise as a result of the amplification and acquisition of subtelomeric elements (and their deletion derivatives) by a large number of telomeres. Hence, even when the primary pathway for telomere replication is defective, an alternative backup pathway can restore telomere function and keep the cell alive.

Publication types

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

MeSH terms

  • Base Sequence
  • Cloning, Molecular
  • DNA Replication*
  • DNA, Fungal / genetics
  • Fungal Proteins / genetics*
  • Genes, Fungal*
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides / chemistry
  • Recombination, Genetic
  • Repetitive Sequences, Nucleic Acid
  • Restriction Mapping
  • Saccharomyces cerevisiae / genetics*
  • Telomere*


  • DNA, Fungal
  • Fungal Proteins
  • Oligodeoxyribonucleotides