Human fibroblasts transfected with an ATM antisense vector respond abnormally to ionizing radiation

Int J Mol Med. 1999 Jul;4(1):43-7. doi: 10.3892/ijmm.4.1.43.


ATM, the gene mutated in ataxia-telangiectasia (A-T), mediates multiple cellular responses to DNA damage. A-T homozygotes have a high risk of cancer and exhibit spontaneous chromosomal instability, and cultured A-T cells react abnormally to ionizing radiation. We have developed an ATM antisense vector that confers an A-T phenotype on normal cells. An episomal antisense vector was created that contained a 1.3 kb segment of the ATM cDNA, and was transfected into normal human fibroblasts. Intracellular levels of ATM protein were typically reduced 10-fold in antisense-expressing (GM639-46alpha) clones. GM639-46alpha clones exhibited the low threshold for radiation-induced apoptosis, low clonogenic survival, and cell cycle defects normally seen in A-T cells. Transfection with the corresponding ATM sense strand vector had no effect on the behavior of normal cells, and neither vector affected the behavior of A-T cells. Our results demonstrate that interference with ATM gene expression recreates the A-T phenotype in normal cells, and provide functional evidence linking the ATM gene to cellular DNA damage responses. The ATM antisense vector should prove a useful tool for studying ATM function in a variety of normal, mutant, and malignant cell lines.

Publication types

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

MeSH terms

  • Apoptosis
  • Ataxia Telangiectasia / genetics
  • Ataxia Telangiectasia Mutated Proteins
  • Base Sequence
  • Cell Cycle Proteins
  • Cell Line, Transformed
  • DNA Damage
  • DNA Primers / genetics
  • DNA, Antisense / genetics
  • DNA-Binding Proteins
  • Fibroblasts / radiation effects
  • Genetic Vectors*
  • Humans
  • Mutation
  • Phenotype
  • Protein-Serine-Threonine Kinases*
  • Proteins / genetics*
  • Radiation Tolerance / genetics
  • Transfection
  • Tumor Suppressor Proteins


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