title: Radiation-induced progressive decreasing in the expression of reverse transcriptase gene of hEST2 and telomerase activity.
abstract: OBJECTIVE
  In order to identify the relationship between telomerase and the biological effect of radiation injury, and investigate the role of human telomerase catalytic subunit gene (hEST2) reverse transcriptase(RT) segment in the expression of telomerase activity.
  
  
  METHODS
  Tumor HeLa cells, KB cells and A431 cells were employed to measure the change in telomerase activity after 60Co-ray irradiation at RNA level and protein level. Quantitative PCR and Northern blotting were used to determine the expression of hEST2 RT segment that encodes seven motifs of the human telomeres, a PCR-based telomeric repeat amplification protocol (TRAP) was used to assay telomerase activity after exposure to radiation.
  
  
  RESULTS
  Both of telomerase activity and the expression hEST2 RT segment were decreased with increasing dosage of radiation. In addition, testing the expression of motifs domain is similar to the measurement of telomerase activity.
  
  
  CONCLUSIONS
  The detection of the hEST2 RT segment by Northern blotting and quantitative PCR are new methods for testing telomerase activity. Furthermore, radiation can cause a dose-dependent decrease in telomerase activity. The effect of radiation on telomerase is one possible reason for the death of cancer cells after irradiation.
authors.affiliation: Shanghai Institute of Radiation Medicine, Department of Immunology, Shanghai Medical University, Shanghai 200032.
authors.forename: H
authors.initials: H
authors.lastname: Zhu
authors.forename: S
authors.initials: S
authors.lastname: Xiong
authors.forename: W
authors.initials: W
authors.lastname: Cheng
mesh_terms: D020134:Catalytic Domain / Q000235:genetics; D045744:Cell Line, Tumor / Q000528:radiation effects; D003037:Cobalt Radioisotopes; D004268:DNA-Binding Proteins; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D007624:KB Cells; D012313:RNA / Q000378:metabolism; D011829:Radiation Dosage; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019098:Telomerase / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D003037:Cobalt Radioisotopes; D004268:DNA-Binding Proteins; D012313:RNA; C509186:TERT protein, human; D019098:Telomerase