The Arabidopsis AtLIG4 gene is required for the repair of DNA damage, but not for the integration of Agrobacterium T-DNA.
The joining of breaks in the chromosomal DNA backbone by ligases in processes of replication, recombination and repair plays a crucial role in the maintenance of genomic stability. Four ATP-dependent ligases, designated DNA ligases I-IV, have been identified in higher eukaryotes, and each one has distinct functions. In mammals and yeast, DNA ligase IV is exclusively involved in the repair of DNA double-strand breaks by non-homologous end joining. Recently, an Arabidopsis thaliana orthologue of the yeast and mammalian DNA ligase IV gene was found and termed AtLIG4. Here we describe the isolation and functional characterisation of a plant line with a T-DNA insertion in the AtLIG4 gene. Plants homozygous for the T-DNA insertion did not display any growth or developmental defects and were fertile. However, mutant seedlings were hypersensitive to the DNA-damaging agents methyl methanesulfonate and X-rays, demonstrating that AtLIG4 is required for the repair of DNA damage. Recently, we showed that a yeast lig4 mutant is deficient in Agrobacterium T-DNA integration. However, using tumorigenesis and germline transformation assays, we found that the plant AtLIG4 mutant is not impaired in T-DNA integration. Thus, in contrast to yeast, DNA ligase IV is not required for T-DNA integration in plants.
van Attikum
Haico
H
Institute of Biology, Leiden University, Clusius Laboratory, Wassenaarseweg 64, 2333 AL, Leiden, The Netherlands.
Bundock
Paul
P
Overmeer
René M
RM
Lee
Lan-Ying
LY
Gelvin
Stanton B
SB
Hooykaas
Paul J J
PJ
D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D004249:DNA Damage; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics*; D018744:DNA, Plant / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D005816:Genetic Complementation Test; D005838:Genotype; D008741:Methyl Methanesulfonate / Q000633:toxicity; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009153:Mutagens / Q000633:toxicity; D009154:Mutation / Q000187:drug effects / Q000528:radiation effects; D030821:Plants, Genetically Modified; D012231:Rhizobium / Q000235:genetics
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D018744:DNA, Plant; D009153:Mutagens; C036483:T-DNA; D008741:Methyl Methanesulfonate; D011088:DNA Ligases; D000072481:DNA Ligase ATP