a, (Top) Metaphase chromosomes after deletion of TRF2 from the indicated cells. Telomeric FISH, green; DAPI, red. (Bottom) Summary of the effect of 53BP1 on telomere fusions at 120 hours after TRF2 deletion.
b, In-gel assay for the 3’ overhang (left) and total telomeric DNA (right) after deletion of TRF2 from 53BP1-proficient and -deficient cells.
c, Quantification of overhang signals in (b) (mean±SD; n=3).
d, IF for presence of γ-H2AX at telomeres after deletion of TRF2 from 53BP1-proficent and -deficient cells.
e, Immunoblots for phosphorylated ATM and Chk2 after TRF2 deletion.
f, Proliferation of MEFs of the indicated genotype and treatment (mean±SD; n=3).