title: Identification of tyrosyl-DNA phosphodiesterase as a novel DNA damage repair enzyme in Arabidopsis.
abstract: Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a key enzyme that hydrolyzes the phosphodiester bond between tyrosine of topoisomerase and 3'-phosphate of DNA and repairs topoisomerase-mediated DNA damage during chromosome metabolism. However, functional Tdp1 has only been described in yeast and human to date. In human, mutations of the Tdp1 gene are involved in the disease spinocerebellar ataxia with axonal neuropathy. In plants, we have identified the functional nuclear protein AtTDP, homolog to human Tdp1 from Arabidopsis (Arabidopsis thaliana). The recombinant AtTDP protein certainly hydrolyzes the 3'-phosphotyrosyl DNA substrates related to repairing in vivo topoisomerase I-DNA-induced damage. The loss-of-function AtTDP mutation displays developmental defects and dwarf phenotype in Arabidopsis. This phenotype is substantially caused by decreased cell numbers without any change of individual cell sizes. The tdp plants exhibit hypersensitivities to camptothecin, a potent topoisomerase I inhibitor, and show rigorous cell death in cotyledons and rosette leaves, suggesting the failure of DNA damage repair in tdp mutants. These results indicate that AtTDP plays a clear role in the repair of topoisomerase I-DNA complexes in Arabidopsis.
authors.affiliation: Department of Biological Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: So-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Hoyeun
authors.initials: H
authors.lastname: Kim
authors.forename: Hyun-Ju
authors.initials: HJ
authors.lastname: Hwang
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Jeong
authors.forename: Sang Hyeon
authors.initials: SH
authors.lastname: Na
authors.forename: Je-Chang
authors.initials: JC
authors.lastname: Woo
authors.forename: Sang-Gu
authors.initials: SG
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002166:Camptothecin / Q000494:pharmacology; D004249:DNA Damage; D004260:DNA Repair; D018744:DNA, Plant / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D059003:Topoisomerase Inhibitors / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D011994:Recombinant Proteins; D059003:Topoisomerase Inhibitors; D010727:Phosphoric Diester Hydrolases; C122147:tyrosyl-DNA phosphodiesterase; D002166:Camptothecin