title: Arabidopsis BRCA2 and RAD51 proteins are specifically involved in defense gene transcription during plant immune responses.
abstract: Systemic acquired resistance (SAR) is a plant immune response associated with both transcriptional reprogramming and increased homologous DNA recombination (HR). SNI1 is a negative regulator of SAR and HR, as indicated by the increased basal expression of defense genes and HR in sni1. We found that the sni1 phenotypes are rescued by mutations in BREAST CANCER 2 (BRCA2). In humans, BRCA2 is a mediator of RAD51 in pairing of homologous DNA. Mutations in BRCA2 cause predisposition to breast/ovarian cancers; however, the role of the BRCA2-RAD51 complex in transcriptional regulation remains unclear. In Arabidopsis, both brca2 and rad51 were found to be hypersusceptible not only to genotoxic substances, but also to pathogen infections. A whole-genome microarray analysis showed that downstream of NPR1, BRCA2A is a major regulator of defense-related gene transcription. ChIP demonstrated that RAD51 is specifically recruited to the promoters of defense genes during SAR. This recruitment is dependent on the SAR signal salicylic acid (SA) and on the function of BRCA2. This study provides the molecular evidence showing that the BRCA2-RAD51 complex, known for its function in HR, also plays a direct and specific role in transcription regulation during plant immune responses.
authors.affiliation: Department of Biology, Duke University, Durham, NC 27708, USA.
authors.forename: Shui
authors.initials: S
authors.lastname: Wang
authors.forename: Wendy E
authors.initials: WE
authors.lastname: Durrant
authors.forename: Junqi
authors.initials: J
authors.lastname: Song
authors.forename: Natalie W
authors.initials: NW
authors.lastname: Spivey
authors.forename: Xinnian
authors.initials: X
authors.lastname: Dong
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D024682:BRCA2 Protein / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D047369:Chromatin Immunoprecipitation; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D054884:Host-Pathogen Interactions; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics; D016685:Mitomycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D011485:Protein Binding; D044224:Pseudomonas syringae / Q000502:physiology; D051135:Rad51 Recombinase / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012459:Salicylates / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D024682:BRCA2 Protein; D019384:Nucleic Acid Synthesis Inhibitors; D012459:Salicylates; D016685:Mitomycin; D051135:Rad51 Recombinase