title: MOS2, a protein containing G-patch and KOW motifs, is essential for innate immunity in Arabidopsis thaliana.
abstract: Innate immunity is critical for sensing and defending against microbial infections in multicellular organisms. In plants, disease resistance genes (R genes) play central roles in recognizing pathogens and initiating downstream defense cascades. Arabidopsis SNC1 encodes a TIR-NBS-LRR-type R protein with a similar structure to nucleotide binding oligomerization domain (Nod) proteins in animals. A point mutation in the region between the NBS and LRR of SNC1 results in constitutive activation of defense responses in the snc1 mutant. Here, we report the identification and characterization of mos2-1, a mutant suppressing the constitutive defense responses in snc1. Analysis of mos2 single mutants indicated that it is not only required for resistance specified by multiple R genes, but also for basal resistance. Map-based cloning of MOS2 revealed that it encodes a novel nuclear protein that contains one G-patch and two KOW domains and has homologs across the animal kingdom. The presence of both G-patch and KOW domains in the MOS2 protein suggests that it probably functions as an RNA binding protein critical for plant innate immunity. Our discovery on the biological functions of MOS2 will shed light on functions of the MOS2 homologs in animals, where they may also play important roles in innate immunity.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Room 301, Vancouver, BC V6T 1Z4, Canada.
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yu Ti
authors.initials: YT
authors.lastname: Cheng
authors.forename: Dongling
authors.initials: D
authors.lastname: Bi
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Palma
authors.forename: Xin
authors.initials: X
authors.lastname: Li
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D001483:Base Sequence; D003001:Cloning, Molecular; D040461:Gene Components; D007113:Immunity, Innate / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary; D044224:Pseudomonas syringae / Q000276:immunology; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000276:immunology; D017422:Sequence Analysis, DNA
chemical_list: D029681:Arabidopsis Proteins; C511880:MOS2 protein, Arabidopsis; D016601:RNA-Binding Proteins; C482739:SNC1 protein, Arabidopsis