Fig 3. ALT-like telomere elongation and long-term telomerase upregulation in HCT116 epithelial cells.

(A) STELA profiles at the 17p chromosome end for the HCT116^ATRX-/o parental; HCT116^{ATRX-/o:DN-hTERT} ALT-like clones 2, 3 and 4; and HCT116^ATRX-/o:Puro with PD points indicated above and the overall mean telomere length in black (represented as orange dotted lines on the blot) displayed below together with allelic mean telomere lengths (red and green) also represented as dotted lines on the blot. The rate of erosion is represented by ΔTel and is expressed in bp/PD. (B) Quantification of telomerase activity (expressed in total product generated: TPG) on the left axis and the C-circle intensity (expressed in arbitrary units: AU) on the right axis. SD was used as error bars and the PD is indicated on the X-axis. (C) C-circle assay slot blots with (+ pol) and without (- pol) polymerase samples with the PD and clone number shown across the bottom. Striped bars indicate telomerase activity and solid bars C-circles.