The Ku70/80 heterodimer is essential for NHEJ (non-homologous end-joining) double-strand break DNA repair and telomere integrity. Inactivation of the KU70 gene in
Riha and Shippen analyzed plants lacking both KU70 and TERT (encoding the catalytic subunit of telomerase). The ku70tert double mutants no longer exhibited the telomere elongation seen in ku70 single mutants. Double-mutants displayed accelerated telomere shortening, reflecting a defect in C-strand maintenance. Also, double-mutants exhibited proliferative defects, but no evidence for chromosome end fusion events.