Fig. 4

CTCF site mutant 17p telomere ends form ultra-fine anaphase bridges (UFBs). a Cells were synchronized by thymidine block and collected between 8–9 h post release and stained with PICH (green) to detect ultra-fine bridges in anaphase cells. b Quantification of a. c Cells were treated as in b and co-stained for PICH protein and 17p chromosome FISH. Representative image of anaphase bridges for wildtype and Mutant 2. White arrows indicate unaffected 17p FISH signals; yellow arrows indicate 17p FISH signals co-localizing with PICH-positive UFBs. d zoomed fields of merged images in c. e Quantification of c. IF/FISH experiments represent average of three biological replicates and SEM; **p < 0.01; ***p < 0.001, measured by Student's t test