Influence of ATM function on telomere metabolism

Oncogene. 1997 Nov 27;15(22):2659-65. doi: 10.1038/sj.onc.1201449.

Abstract

The ATM gene product, which is defective in the cancer-prone disorder ataxia telangiectasia, has been implicated in mitogenic signal transduction, chromosome condensation, meiotic recombination and cell cycle control. The ATM gene has homology with the TEL1 gene of yeast, mutations of which lead to shortened telomeres. To test the hypothesis that the ATM gene product is involved in telomere metabolism, we examined telomeric associations (TA), telomere length, and telomerase activity in human cells expressing either dominant-negative or complementing fragments of the ATM gene. The phenotype of RKO colorectal tumor cells expressing ATM fragments containing a leucine zipper (LZ) motif mimics that of ataxia telangiectasia (A-T) cells. These transfected RKO cells relative to transfected controls had a higher frequency of cells with TA and shortened telomeres, but no detectable change in telomerase activity. In addition, the percentage of cells with TA after gamma irradiation was higher in the transfected RKO cells with dominant negative activity of the ATM gene, compared to control cells. SV40 transformed fibroblasts derived from an A-T patient and transfected with a complementing carboxyl terminal kinase region of the ATM gene had a reduced frequency of cells with TA, with no effect on the telomere length or telomerase activity. The present studies using isogenic cells with manipulated ATM function demonstrate a role for the ATM gene product in telomere metabolism.

Publication types

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

MeSH terms

  • Animals
  • Ataxia Telangiectasia / genetics
  • Ataxia Telangiectasia Mutated Proteins
  • Carcinoma / genetics
  • Carcinoma / radiotherapy
  • Cell Cycle Proteins
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / radiotherapy
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Fibroblasts
  • G1 Phase / genetics
  • G2 Phase / genetics
  • Humans
  • Leucine Zippers / genetics
  • Metaphase / genetics
  • Protein-Serine-Threonine Kinases*
  • Proteins / genetics*
  • Proteins / metabolism
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Telomerase / metabolism
  • Telomere / genetics*
  • Telomere / metabolism*
  • Transfection
  • Tumor Cells, Cultured
  • Tumor Suppressor Proteins

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Proteins
  • Recombinant Proteins
  • Tumor Suppressor Proteins
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Protein-Serine-Threonine Kinases
  • Telomerase