Cells deficient for DNMT1 and 3b display normal telomerase activity.

<p>(<b>A</b>) Western blot analysis of hTERT-expression in HCT116 parental (par) or DNMT1 and 3b double KO (DKO) infected cells. Numbers at the bottom are the ratios between hTERT and PCNA (loading control) signals, expressed as fold increase over hTERT-infected parental cells. (<b>B</b>) qRT-PCR analysis of the steady-state levels of TERRA transcripts originating from 10q and 15q chromosome ends expressed as fold increase over ev-infected par cells. Bars and error bars are averages and standard deviations from three independent experiments. (<b>C</b>) Analysis of TRAP amplification products from the indicated cells lines. Three different amounts of total proteins were used for each cell line and to control for specificity one sample was pre-treated with RNase A. Control primers amplifying an internal control (IC) were included in all reactions. (<b>D</b>) Quantification of telomerase activity in the indicated samples using qRT-PCR-based TRAP assays. Bars and error bars are averages and standard deviations from three independent experiments, after normalization through ev-infected parental cell samples. Numbers indicate P-values (*: P<0.01). (<b>E</b>) qRT-PCR-based quantification of 10q and 15q TERRA transcripts in TRAP extracts (ext) or in cell pellets left after extraction (plt). Relative TERRA amounts are expressed as fractions of total TERRA molecules from pellet plus extract. Bars and error bars are averages and standard deviations from three independent experiments.