Table 2.

Comparison of relative steady-state hTR levels

Cell lineDescriptionRelative hTR levela quantitated by:
Northern hybridizationbRNase protection assayQuantitative RT-PCR
Telomerase-negative cells
 BJNormal foreskin fibroblasts111
 IMR90Normal lung fibroblasts1.0 ± 0.6
 HME31Normal mammary epithelial cells0.91 ± 0.06
 HME31 E6 precrisisPrecrisis HME31 cells expressing E61.6 ± 0.2
Cells expressing exogenous hTERT
 BJ hTERTDerived from BJ2.6 ± 0.32.31.3
 IMR90 hTERTDerived from IMR901.4 ± 0.4
 HME31 hTERTDerived from HME312.7 ± 0.2
 HME31 E6 hTERTDerived from HME31 E6 precrisis3.4 ± 0.7
Cells expressing endogenous hTERT
 HME31 E6 immortalPostcrisis HME31 cells expressing E66.0 ± 0.3
 IMR90 T-AgSV40 T-Ag-immortalized IMR90 cells5.0 ± 0.9
 H1299Non-small-lung carcinoma cells14 ± 1.01916
  • a The hTR levels for all assays are expressed relative to those in BJ cells, which were set as 1.

  • b Values are means from three experiments ± 1 standard deviation.