The RNA binding protein Tudor-SN is essential for stress tolerance and stabilizes levels of stress-responsive mRNAs encoding secreted proteins in Arabidopsis.
Tudor-SN (TSN) copurifies with the RNA-induced silencing complex in animal cells where, among other functions, it is thought to act on mRNA stability via the degradation of specific dsRNA templates. In plants, TSN has been identified biochemically as a cytoskeleton-associated RNA binding activity. In eukaryotes, it has recently been identified as a conserved primary target of programmed cell death-associated proteolysis. We have investigated the physiological role of TSN by isolating null mutations for two homologous genes in Arabidopsis thaliana. The double mutant tsn1 tsn2 displays only mild growth phenotypes under nonstress conditions, but germination, growth, and survival are severely affected under high salinity stress. Either TSN1 or TSN2 alone can complement the double mutant, indicating their functional redundancy. TSN accumulates heterogeneously in the cytosol and relocates transiently to a diffuse pattern in response to salt stress. Unexpectedly, stress-regulated mRNAs encoding secreted proteins are significantly enriched among the transcripts that are underrepresented in tsn1 tsn2. Our data also reveal that TSN is important for RNA stability of its targets. These findings show that TSN is essential for stress tolerance in plants and implicate TSN in new, potentially conserved mechanisms acting on mRNAs entering the secretory pathway.
Frei dit Frey
Nicolas
N
Institut des Sciences du Végétal, Centre National de la Recherche Scientifique 2355, Gif sur Yvette cedex, France.
Muller
Philippe
P
Jammes
Fabien
F
Kizis
Dimosthenis
D
Leung
Jeffrey
J
Perrot-Rechenmann
Catherine
C
Bianchi
Michele Wolfe
MW
D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics*; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D021381:Protein Transport / Q000187:drug effects; D020871:RNA Stability / Q000187:drug effects / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D034743:RNA-Induced Silencing Complex / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology; D012987:Soil; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*
D029681:Arabidopsis Proteins; C000599172:At5g07350 protein, Arabidopsis; C000599171:At5g61780 protein, Arabidopsis; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D034743:RNA-Induced Silencing Complex; D012987:Soil; D012965:Sodium Chloride