Molecular characterization of nucleus-localized RNA-binding proteins from higher plants.
We report the isolation and characterization of genes from the higher plants Arabidopsis, spinach and tobacco which code for nucleus-localized RNA-binding proteins. Common features of these polypeptides are glycine/arginine-rich regions with several RGG repeats at their N- and C-termini, which are sufficient for RNA binding in northwestern assays. All polypeptides analysed contain two basic bipartite nuclear localization signals and translational fusions harbouring these regions with the beta-glucuronidase gene direct the fusion proteins into the nucleus. Nuclear localization was confirmed by cellular fractionation with a polyclonal antiserum raised against the over-expressed tobacco protein NtRGG1p. Two or three copies of related RGG genes appear to be present in the analysed organisms and the expression of some of them is regulated: a tobacco gene is light-regulated and a spinach gene is preferentially expressed in roots. Possible biological functions of this class of RNA-binding proteins as well as structure/function relationships related to the modular structure are discussed.
Landsberger
Martin
M
Institut für Allgemeine Botanik der Friedrich-Schiller-Universität, Lehrstuhl für Pflanzenphysiologie, Jena, Germany.
Lorković
Zdravko J
ZJ
Oelmüller
Ralf
R
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D018724:Spinacia oleracea / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
D018076:DNA, Complementary; D018744:DNA, Plant; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012313:RNA; D005966:Glucuronidase