Figure 4.

APBs, C-circles, and telomere lengths increase in LAPC-4 ATRX^KO clones lacking telomerase activity. Representative images of telomere FISH (red) and PML immunoblotting (green) from (A) LAPC-4 ATRX^KO 1 and LAPC-4 ATRX^KO 1;TERC^mut; (B) LAPC-4 ATRX^KO 2 and LAPC-4 ATRX^KO 2;TERC^mut. Arrows indicate examples of ALT-associated PML Bodies (APBs). Cells were scored for APBs in (C) LAPC-4 ATRX^KO 1;TERC^mut and LAPC-4 ATRX^KO 2;TERC^mut. P-values were determined using two-sided t-tests. C-circle assay of (D) LAPC-4 ATRX^KO 1;TERC^mut and (F) LAPC-4 ATRX^KO 2;TERC^mut. The relative quantity of C-circle was assessed from blots of (E) LAPC-4 ATRX^KO 1;TERC^mut and (G) LAPC-4 ATRX^KO 2;TERC^mut. P-values were determined using unpaired two-sided t-tests. Representative telomere restriction fragment (TRF) southern blots of (H) LAPC-4 ATRX^KO 1;TERC^mut and (I) LAPC-4 ATRX^KO 2;TERC^mut. Intensity traces of the distribution of TRFs is shown. PD = population doubling.