Tankyrase 1-induced telomere elongation is telomerase-dependent.
(A–C) Generation of a stable WI38 cell line expressing
telomerase. WI38 cells at PD 4 expressing vector control (V) or telomerase
(TERT) were analyzed for telomerase expression by immunoblotting whole-cell
extracts with anti-TERT 374 antibody (A), or for telomerase activity
by TRAP (telomere repeat amplification protocol; B) or for telomere
length by Southern blot analysis (C). (D–F) Analysis
of stable WI38 cells expressing telomerase (WI38-TERT) and tankyrase 1
alleles. WI38-TERT cells expressing vector control (V), FN-tankyrase1.WT (WT),
or FN-tankyrase1.HE/A (HE/A) were analyzed at PD 9 by immunoblotting
whole-cell extracts with the antibodies anti-tankyrase 1 376 (TNKS1),
anti-poly(ADP-ribose) (PAR), anti-telomerase (TERT), or anti-TRF1 415
(D); or at PD 11 for telomerase activity by TRAP (E); or at
the indicated PDs for telomere length by Southern blot analysis
(F).