Enod40, a short open reading frame-containing mRNA, induces cytoplasmic localization of a nuclear RNA binding protein in Medicago truncatula.
In eukaryotes, diverse mRNAs containing only short open reading frames (sORF-mRNAs) are induced at specific stages of development. Their mechanisms of action may involve the RNA itself and/or sORF-encoded oligopeptides. Enod40 genes code for highly structured plant sORF-mRNAs involved in root nodule organogenesis. A novel RNA binding protein interacting with the enod40 RNA, MtRBP1 (for Medicago truncatula RNA Binding Protein 1), was identified using a yeast three-hybrid screening. Immunolocalization studies and use of a MtRBP1-DsRed2 fluorescent protein fusion showed that MtRBP1 localized to nuclear speckles in plant cells but was exported into the cytoplasm during nodule development in enod40-expressing cells. Direct involvement of the enod40 RNA in MtRBP1 relocalization into cytoplasmic granules was shown using a transient expression assay. Using a (green fluorescent protein)/MS2 bacteriophage system to tag the enod40 RNA, we detected in vivo colocalization of the enod40 RNA and MtRBP1 in these granules. This in vivo approach to monitor RNA-protein interactions allowed us to demonstrate that cytoplasmic relocalization of nuclear proteins is an RNA-mediated cellular function of a sORF-mRNA.
Campalans
Anna
A
Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, 91198 Gif sur Yvette, France.
Kondorosi
Adam
A
Crespi
Martin
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D003593:Cytoplasm / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D029902:Medicago / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D019697:Onions / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D062085:RNA, Long Noncoding; D012333:RNA, Messenger / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics*; D022661:RNA, Untranslated / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques
D018744:DNA, Plant; D004268:DNA-Binding Proteins; C405430:ENOD40 RNA; D009687:Nuclear Proteins; D010940:Plant Proteins; D062085:RNA, Long Noncoding; D012333:RNA, Messenger; D018749:RNA, Plant; D022661:RNA, Untranslated; D011993:Recombinant Fusion Proteins