ATP-dependent DNA helicase 2 subunit KU80; Single-stranded DNA-dependent ATP-dependent helicase. Involved in DNA non-homologous end joining (NHEJ) required for double- strand break repair. When associated with KU70, binds to double- stranded telomeric and non-telomeric DNA sequences, but not to single- stranded DNA. Plays a role in maintaining telomere length. Acts as a negative regulator of telomerase. Binds to and recombines double- stranded T-DNA molecules. Belongs to the ku80 family.

DNA ligase 4; Efficiently joins single-strand breaks in a double-stranded polydeoxynucleotide in an ATP-dependent reaction. Involved in DNA non- homologous end joining (NHEJ) required for double-strand break repair. May be involved for T-DNA integration even if not absolutely required. Seems to be dispensable under normal growth conditions. Belongs to the ATP-dependent DNA ligase family.

DNA repair protein XRCC4; May be involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair. May bind to DNA. The LIG4- XRCC4 complex is probably responsible for the NHEJ ligation step, and XRCC4 may enhance the joining activity of LIG4 (By similarity).

Telomerase reverse transcriptase; Telomerase is a ribonucleoprotein enzyme essential for the replication of chromosome termini in most eukaryotes. It elongates telomeres. It is a reverse transcriptase that adds simple sequence repeats to chromosome ends by copying a template sequence within the RNA component of the enzyme. Required to prevent genome instability induced by breakage-fusion-bridge (BFB) cycles. Can extend completely non-telomeric sequences using RNA template in vitro.

DNA repair protein RAD50; Implicated in double-strand breaks (DSBs) repair by non- homologous end joining (NHEJ). Involved in telomere maintenance. Involved in telomerase action on chromosome ends. Required during meiosis for both male and female gametophytic development, for pairing and synapsis of homologous chromosomes during the early stages of meiotic recombination, especially during the pachytene stage of the first division. Belongs to the SMC family. RAD50 subfamily.

Double-strand break repair protein MRE11; Involved in DNA double-strand break repair (DSBR). Possesses single-strand endonuclease activity and double-strand-specific 3'-5' exonuclease activity. Also involved in meiotic DSB processing (By similarity); Belongs to the MRE11/RAD32 family.

DNA polymerase lambda; Repair polymerase involved in base excision repair (BER) and responsible for repair of lesions that give rise to abasic (AP) sites in DNA. Has both DNA polymerase and terminal transferase activities. Has a 5'-deoxyribose-5-phosphate lyase (dRP lyase) activity (By similarity). Involved in the repair of transposon-induced DNA double strand breaks (DSBs). Involved in repair of UV-B- mediated DNA damage during seedling development through an excision repair mechanism. Involved the repair of DSBs induced by high salinity and DNA cross-linking agent. Functions via the [...]

DNA ligase 1; Essential protein. DNA ligase that seals nicks in double- stranded DNA during DNA replication, DNA recombination and DNA repair. Involved in repair of both single strand breaks (SSBs) and double strand breaks (DSBs). Required in the endosperm for embryogenesis, probably to repair DNA-breaks generated by DME.

DNA-repair protein XRCC1; Corrects defective DNA strand-break repair and sister chromatid exchange following treatment with ionizing radiation and alkylating agents (By similarity). Involved in DNA demethylation pathway by stimulating cytosine methylation (5-meC) excision, gap tailoring, and DNA ligation.