RAD54 promotes Alternative Lengthening of Telomeres by mediating branch migration (2020)
Figure 4

Figure 4: RAD54 promotes post-synaptic processing of recombination intermediates at ALT telomeres

A Representative images of combined IF and DNA FISH for BLM (IF) and telomeres (FISH). HuO9 cells were transfected with 20nM siRAD54#2 for 48 hours. Scale bars = 10 µm

B Quantification of data shown in A. Cells were counted positive if they contained at least 1 colocalization event between BLM and telomeres. Data were normalized to mock condition of each repeat. At least 100 cells per condition per repeat were counted, n=3. Values shown are mean±sd. Conditions were analyzed using unpaired two-tailed student's t-test.

C Representative images of IF-DNA FISH for MUS81 and telomeres. HuO9 cells were transfected with 20nM siRAD54 #2 for 48 hours prior to staining. Scale bars = 10 µm

D Quantification of data shown in C. Cells were counted positive if they contained at least 1 colocalization event between MUS81 and telomeres. At least 100 cells per condition were counted per repeat. n=5, values shown are mean±sd. Conditions were analyzed using unpaired two-tailed student's t-test.

E Representative images of HuO9 and SaOS2 chromosomes with or without an exchange event. Colocalization of green and red signal indicates an exchange event.

F Quantification of telomere sister chromatid exchange events. Cells were transfected with 20nM of siRNA for 48 hours prior to the addition of BrdU/BrdC. Metaphases were imaged by confocal microscopy and each data point represents a metaphase. For each condition, there were 3 biological repeats with a total of at least 1300 chromosome ends quantified. Values shown are mean±sem. Conditions were analyzed using two-way ANOVA followed by Sidak's test.

G Representative images of UFB detection staining for PICH in HuO9 cells. Cells were transfected with 20nM of noted siRNAs for 72 hrs. Scale bars = 10 µm

H Quantification of data shown in G. Anaphases were scored from 4 independent experiments (mock), or 3 independent experiments (remaining conditions). Anaphases were considered positive for UFB if there was PICH staining between DAPI bodies. Single knockdown conditions had >50 anaphases scored. Combined knockdown conditions had >88 anaphases scored. Values shown are mean±sd. Conditions were compared using one-way ANOVA followed by Dunnett's multiple comparison test.

I Quantification of data shown in G. Number of PICH stained UFBs counted per anaphase. Values shown are total counts over 3 independent experiments, shown mean±sem. Total number of anaphases per condition were as follows: Mock n=134, siBLM/siSLX4 n=90, siRAD54/siSLX4 n=96, siRAD54/siBLM/siSLX4 n=88. Conditions were compared using Kruskal-Wallis test followed by Dunn's multiple comparison test.

J Representative images of UFB staining for TRF2 in HuO9 cells. Cells were transfected with 20nM siRAD54#2 alone or cotransfected siRAD54#2 and siSLX4 for 72 hours prior to staining. Scale bars = 10 µm

K Quantification of data shown in J. Anaphases were scored from 3 independent experiments. A total of 90 anaphases were scored per condition. Values shown are mean±sd. Conditions were compared using one-way ANOVA followed by Dunnett's multiple comparison test.

L Quantification of micronuclei from HuO9 cells transfected with siRAD54#2 alone or siRAD54#2 cotransfected with siSLX4 for 48 hours. Micronuclei containing telomeric DNA were identified using DAPI and telomere FISH. Micronuclei were normalized to the number of nuclei counted. Values shown are mean±sd of n=3 biological replicates. Conditions were compared using one-way ANOVA followed by Dunnett's multiple comparison test.