The Zinc Finger Domains (Znf) of TZAP directly bind telomeric repeats. (A) Schematic representation of the constructs used to show that the Zinc finger domains of TZAP are sufficient for telomeric localization. (B) IF-FISH for telomeric localization of the indicated constructs in TRF2 null MEFs (C) Metaphase spreads derived from TRF2 null MEFs expressing the indicated constructs were stained for telomeric DNA (green) and DAPI (red). (D) Genomic DNA isolated from TRF2 proficient (-OHT) or TRF2 null (+OHT) MEFs expressing the indicated constructs was digested with MboI, resolved on a pulsed field gel, and probed using radioactive telomeric probe. (E) The terminal Zinc finger domains (#9,10 and 11) of TZAP are required for telomeric localization as shown by Flag-ChIP in U2OS cells expressing the indicated Flag-tagged constructs. (F) A recombinant HisMBP-tagged TZAPZnf9–11 allele was expressed in bacteria, purified and used in gel shift assays. Left panel: HisMBP-TZAPZnf9–11 binds telomeric repeats and is supershifted by a His-tag antibody. Right panel: competition assay using increasing amounts (0x, 1x, 10x, 100x, 1000x fold molar excess) of cold non-telomeric or telomeric competitor dsDNA.