Abstract
Vertebrate nucleolin is an abundant RNA-binding protein in the dense fibrillar component of active nucleoli. Nucleolin is modular in composition. Its amino-terminal third contains alternating acidic and basic domains, its middle section contains four consensus RNA-binding domains (cRBDs), and its carboxy-terminus contains a distinctive glycine/arginine-rich (GAR) domain with several RGG motifs. The arginines within these motifs are asymmetrically dimethylated. Several laboratories have shown that the GAR domain is necessary but not sufficient for the efficient localization of nucleolin to nucleoli. We examined the distribution of endogenous fibrillarin, Nopp140, and B23 when full-length and ΔGAR nucleolin were expressed exogenously as enhanced green fluorescent protein (EGFP)-tagged fusions. Only B23 redistributed when ΔGAR-EGFP was expressed at moderate to high levels, suggesting an in vivo interaction between nucleolin and B23. Next we substituted all ten arginines within the GAR domain of Chinese hamster ovary (CHO) nucleolin with lysines to test the hypothesis that methylation of the carboxy GAR domain is necessary for the nucleolar association of nucleolin. The lysine-substituted mutant was not an in vitro substrate for the yeast protein methyltransferase, Hmt1p/Rmt1. It was, however, able to associate properly with interphase nucleoli and with interphase pre-nucleolar bodies upon recovery from hypotonic shock. We conclude, therefore, that although the GAR domain is necessary for the efficient localization of nucleolin to nucleoli, methylation of this domain is not required for proper nucleolar localization.
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Allain FH, Bouvet P, Diechmann T, Felgon J (2000) Molecular basis of sequence-specific recognition of pre-ribosomal RNA by nucleolin. EMBO J 19:6870–6881
Bouvet P, Diaz JJ, Kindbeiter K, Madjar JJ, Amalric F (1998) Nucleolin interacts with several ribosomal proteins through its RGG domain. J Biol Chem 273:19025–19029
Brahms H, Raymackers J, Union A, de Keyser F, Meheus L, Luhrmann R (2000) The C-terminal RG bipeptide repeats of the spliceosomal SM proteins D1 and D3 contain symmetrical dimethylarginines, which form a major D-cell epitope for anti-SM autoantibodies. J Biol Chem 275:17122–17129
Cartegni L, Maconi M, Morandi E, Cobianchi F, Riva S, Biamonti G (1996) hnRNP A1 selectively interacts through its Gly-rich domain with different RNA-binding proteins. J Mol Biol 259:337–348
Chen C, Okayama H (1988) Calcium phosphate-mediated gene transfer: a highly efficient system for stably transforming cells with plasmid DNA. Biotechniques 6:632–638
Cobianchi F, Karpel RL, Williams KR, Notario V, Wilson SH (1988) Mammalian heterogeneous nuclear ribonucleoprotein complex protein A1. J Biol Chem 263:1063–1071
Créancier L, Prats H, Zanibellato C, Amalric F, Bugler B (1993) Determination of the functional domains involved in nucleolar targeting of nucleolin. Mol Biol Cell 4:1239–1250
Frankel A, Clarke S (1999) RNase treatment of yeast and mammalian cell extracts affects in vitro substrate methylation by type I protein arginine N-methyltransferases. Biochem Biophys Res Commun 259:391–400
Friesen WJ, Massenet S, Paushkin S, Wyce A, Dreyfuss G (2001a) SMN, the product of the spinal muscular atrophy gene, binds preferentially to dimethylarginine-containing protein targets. Mol Cell 7:1111–1117
Friesen WJ, Paushkin S, Wyce A, Massenet S, Pesiridis GS, Van Duyne G, Rappsilber J, Mann M, Dreyfuss G (2001b) The methylosome, a 20S complex containing JBP1 and pICln, produces dimethylarginine-modified Sm proteins. Mol Cell Biol 21:8289–8300
Gary JD, Clarke S (1998) RNA and protein interactions modulated by protein arginine methylation. Prog Nucleic Acid Res Mol Biol 61:65–131
Gary JD, Lin W-J, Yang MC, Herschman HR (1996) The predominant protein-arginine methyltransferase from Saccharomyces cerevisiae. J Biol Chem 271:12585–12594
Ghisolfi L, Gérard J, Amalric F, Erard M (1992) The glycine-rich domain of nucleolin has an unusual supersecondary structure responsible for its RNA-helix-destabilizing properties. J Biol Chem 267:2955–2959
Ghisolfi-Nieto L, Joseph G, Puvion-Dutilleul F, Amalric F, Bouvet P (1996) Nucleolin is a sequence-specific RNA-binding protein: characterization of targets on pre-ribosomal RNA. J Mol Biol 260:34–53
Ginisty H, Amalric F, Bouvet P (1998) Nucleolin functions in the first step of ribosomal RNA processing. EMBO J 17:1476–1486
Ginisty H, Sicard H, Roger B, Bouvet P (1999) Structure and functions of nucleolin. J Cell Sci 112:761–772
Hanakahi LA, Bu Z, Maizels N (2000) The C-terminal domain of nucleolin accelerates nucleic acid annealing. Biochemistry 39:15493–15499
Heine MA, Rankin ML, DiMario PJ (1993) The gly/arg-rich (GAR) domain of Xenopus nucleolin facilitates in vitro nucleic acid binding and in vivo nucleolar localization. Mol Biol Cell 4:1189–1204
Henry MF, Silver PA (1996) A novel methyltransferase (Hmt1p) modifies poly(A)+ -RNA-binding proteins. Mol Cell Biol 16:3668–3678
Kumar A, Wilson SH (1990) Studies of the strand-annealing activity of mammalian hnRNP complex protein A1. Biochemistry 29:10717–10722
Lapeyre B, Amalric F, Ghaffari SH, Venkatarama R, Dumbar TS, Olson MOJ (1986) Protein and cDNA sequence of a glycine-rich, dimethylarginine-containing region located near the carboxy-terminal end of nucleolin (C23 and 100 kDa). J Biol Chem 261:9167–9173
Lapeyre B, Bourbon H, Amalric F (1987) Nucleolin, the major nucleolar protein of growing eukaryotic cells: an unusual protein structure revealed by the nucleotide sequence. Proc Natl Acad Sci U S A 84:1472–1476
Li Y-P, Busch RK, Valdez BC, Busch H (1996) C23 interacts with B23, a putative nucleolar-localization-signal-binding protein. Eur J Biochem 237:153–158
Liu Q, Dreyfuss G (1995) In vivo and in vitro arginine methylation of RNA-binding proteins. Mol Cell Biol 15:2800–2808
Lischwe MA, Cook RG, Ahn YS, Yeoman LC, Busch H (1985) Clustering of glycine and NG,NG-dimethylarginine in nucleolar protein C23. Biochemistry 24:6025–6028
McBride AE, Silver PA (2001) State of the arg: protein methylation at arginine comes of age. Cell 106:5–8
Meßmer B, Dreyer C (1993) Requirements for nuclear translocation and nucleolar accumulation of nucleolin of Xenopus laevis. Eur J Cell Biol 61:369–382
Nadler SG, Merrill BM, Roderts WJ, Keating KM, Lisbin MJ, Barnett SF, Wilson SH, Williams KR (1991) Interactions of the A1 heterogeneous nuclear ribonucleoprotein and its proteolytic derivative UP1, with RNA and DNA: evidence for multiple RNA binding domains and salt-dependent binding mode transitions. Biochemistry 30:2968–2976
Reimer G, Pollard KM, Penning CA, Ochs RL, Lischwe MA, Busch H, Tan EM (1987) Monoclonal autoantibody from a (New Zealand black × New Zealand white)F1 mouse and some scleroderma sera target an Mr 34,000 nucleolar protein of the U3 RNP particle. Arthritis Rheum 30:793–800
Schmidt-Zachmann MS, Nigg EA (1993) Protein localization to the nucleolus; a search for targeting domains in nucleolin. J Cell Sci 105:799–806
Shen EC, Henry MF, Weiss VH, Valentini SR, Silver PA, Lee MS (1998) Arginine methylation facilitates the nuclear export of hnRNP proteins. Genes Dev 12:679–691
Tao J, Frankel AD (1992) Specific binding of arginine to TAR RNA. Proc Natl Acad Sci U S A 89:2723–2726
Tuteja N, Huang NW, Skopac D, Tuteja R, Hrvatic S, Zhang J, Pongor S, Joseph G, Faucher C, Amalric F, Falaschi A (1995) Human DNA helicase IV is nucleolin, an RNA helicase modulated by phosphorylation. Gene 160:143–148
Varani G, Nagai K (1998) RNA recognition by RNP proteins during RNA processing. Annu Rev Biophys Biomol Struct 27:407–445
Waggener JM, DiMario PJ (2002) Two splice variants of Nopp140 in Drosophila melanogaster. Mol Biol Cell 13:362–381
Zatsepina OV, Dudnic OA, Todorov IT, Thiry M, Spring H, Trendelenburg MF (1997) Experimental induction of prenucleolar bodies (PNBs) in interphase cells: interphase PNBs show similar characteristics as those typically observed at telophase of mitosis in untreated cells. Chromosoma 105:418–430
Acknowledgements
We thank Drs. Ben Valdez, Tom Meier, and Robert Ochs for antibodies directed against B23, Nopp140, and fibrillarin, respectively. We thank Dr. Michael Henry for the cDNA encoding Hmt1p/Rmt1. We also thank LSU undergraduate student Kathleen Yoho for technical assistance in helping us select stably transfected HeLa cells. This work was supported by the National Science Foundation, award MCB-9204796.
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Edited by: S.A. Gerbi
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Pellar, G.J., DiMario, P.J. Deletion and site-specific mutagenesis of nucleolin's carboxy GAR domain. Chromosoma 111, 461–469 (2003). https://doi.org/10.1007/s00412-003-0231-y
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DOI: https://doi.org/10.1007/s00412-003-0231-y