Identification of plant RAD52 homologs and characterization of the Arabidopsis thaliana RAD52-like genes.
RADiation sensitive52 (RAD52) mediates RAD51 loading onto single-stranded DNA ends, thereby initiating homologous recombination and catalyzing DNA annealing. RAD52 is highly conserved among eukaryotes, including animals and fungi. This article reports that RAD52 homologs are present in all plants whose genomes have undergone extensive sequencing. Computational analyses suggest a very early RAD52 gene duplication, followed by later lineage-specific duplications, during the evolution of higher plants. Plant RAD52 proteins have high sequence similarity to the oligomerization and DNA binding N-terminal domain of RAD52 proteins. Remarkably, the two identified Arabidopsis thaliana RAD52 genes encode four open reading frames (ORFs) through differential splicing, each of which specifically localized to the nucleus, mitochondria, or chloroplast. The A. thaliana RAD52-1A ORF provided partial complementation to the yeast rad52 mutant. A. thaliana mutants and RNA interference lines defective in the expression of RAD52-1 or RAD52-2 showed reduced fertility, sensitivity to mitomycin C, and decreased levels of intrachromosomal recombination compared with the wild type. In summary, computational and experimental analyses provide clear evidence for the presence of functional RAD52 DNA-repair homologs in plants.
Department of Plant Sciences, Weizman Institute of Science, Rehovot, Israel.
Aviva
A
Samach
Cathy
C
Melamed-Bessudo
Naomi
N
Avivi-Ragolski
Shmuel
S
Pietrokovski
Avraham A
AA
Levy
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D019295:Computational Biology; D019143:Evolution, Molecular; D020440:Gene Duplication; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005816:Genetic Complementation Test; D059765:Homologous Recombination; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D016685:Mitomycin / Q000494:pharmacology; D016366:Open Reading Frames; D010802:Phylogeny; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012326:RNA Splicing; D051135:Rad51 Recombinase / Q000235:genetics* / Q000378:metabolism; D051721:Rad52 DNA Repair and Recombination Protein / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D029681:Arabidopsis Proteins; D020033:Protein Isoforms; C497197:RAD52 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; D016685:Mitomycin; C495146:ATRAD51 protein, Arabidopsis; D051135:Rad51 Recombinase