Characteristics of transformed human cells expressing FLAG-hTERT NAAIRS mutants

  • a Presence (+) or absence (−) of hTERT mRNA as determined by RT-PCR.

  • b Presence (+) or absence (−) of FLAG-hTERT protein in 293 cells as determined by immunoblotting with an α-FLAG antibody.

  • c In vitro telomerase activity for each mutant was determined by normalizing activity to the internal standard and then expressed as a percentage of wild-type FLAG-hTERT activity: ++ (>50%), + (50 to 15%), +/− (<15%), − (undetectable).

  • d Crisis was defined as the point whereby cells failed to reach confluency after a minimum of 20 days. EL denotes an extended lifespan.