Binds specifically to the plant telomeric double-stranded DNA sequences 5'-GGTTTAG-3'. At least 4 repeats of telomeric sequences are required for binding. Induces DNA bending. Homodimer and heterodimer with TRP2 and TRP3. Interacts with KU70. Expressed ubiquitously. Highest expression in flowers and leaves. A N-terminal domain (80-269) is responsible for the interaction with KU70. The C-terminal domain (464-578) is sufficient for telomere binding. No visible phenotype, probably due to redundancy.