small nuclear ribonucleoproteins


Summary: Highly conserved nuclear RNA-protein complexes that function in RNA processing in the nucleus, including pre-mRNA splicing and pre-mRNA 3'-end processing in the nucleoplasm, and pre-rRNA processing in the nucleolus (see RIBONUCLEOPROTEINS, SMALL NUCLEOLAR).

Top Publications

  1. Battle D, Kasim M, Wang J, Dreyfuss G. SMN-independent subunits of the SMN complex. Identification of a small nuclear ribonucleoprotein assembly intermediate. J Biol Chem. 2007;282:27953-9 pubmed
    ..These findings demonstrate a modular nature of the SMN complex and identify a new intermediate in the snRNP assembly process. ..
  2. Sleeman J. A regulatory role for CRM1 in the multi-directional trafficking of splicing snRNPs in the mammalian nucleus. J Cell Sci. 2007;120:1540-50 pubmed
    ..Newly imported splicing small nuclear ribonucleoproteins (snRNPs) exchange between Cajal bodies (CBs) within a nucleus and access the cytoplasm, but are ..
  3. Lau C, Bachorik J, Dreyfuss G. Gemin5-snRNA interaction reveals an RNA binding function for WD repeat domains. Nat Struct Mol Biol. 2009;16:486-91 pubmed publisher
    ..The WD repeat domain is thus a previously undescribed RNA binding domain, and we suggest that the presence of WD repeats should be considered as predictive of potential function in RNA binding. ..
  4. Will C, Schneider C, Hossbach M, Urlaub H, Rauhut R, Elbashir S, et al. The human 18S U11/U12 snRNP contains a set of novel proteins not found in the U2-dependent spliceosome. RNA. 2004;10:929-41 pubmed
    ..The presence of unique U11/U12 snRNP proteins in the U12-type spliceosome provides insight into potential evolutionary relationships between the major and minor spliceosome. ..
  5. Pessa H, Ruokolainen A, Frilander M. The abundance of the spliceosomal snRNPs is not limiting the splicing of U12-type introns. RNA. 2006;12:1883-92 pubmed
    ..Thus our results suggest that the cellular abundance of the snRNPs does not limit U12-type intron splicing under normal conditions. ..
  6. Nesic D, Tanackovic G, Kramer A. A role for Cajal bodies in the final steps of U2 snRNP biogenesis. J Cell Sci. 2004;117:4423-33 pubmed
    The biogenesis of Sm-type small nuclear ribonucleoproteins (snRNPs) involves the export of newly transcribed small nuclear RNAs (snRNAs) to the cytoplasm, assembly with seven common proteins and modification at the 5' and 3' termini...
  7. Narayanan U, Achsel T, Luhrmann R, Matera A. Coupled in vitro import of U snRNPs and SMN, the spinal muscular atrophy protein. Mol Cell. 2004;16:223-34 pubmed
    Cytoplasmic assembly of Sm-class small nuclear ribonucleoproteins (snRNPs) is a central process in eukaryotic gene expression...
  8. Khusial P, Vaidya K, Zieve G. The symmetrical dimethylarginine post-translational modification of the SmD3 protein is not required for snRNP assembly and nuclear transport. Biochem Biophys Res Commun. 2005;337:1119-24 pubmed
    ..This suggests this modification is not essential for maturation of the SmD3 protein. ..
  9. Walker M, Rajendra T, Saieva L, Fuentes J, Pellizzoni L, Matera A. SMN complex localizes to the sarcomeric Z-disc and is a proteolytic target of calpain. Hum Mol Genet. 2008;17:3399-410 pubmed publisher
    ..These results support the view that the SMN complex performs a muscle-specific function at the Z-discs. ..

More Information


  1. Shpargel K, Matera A. Gemin proteins are required for efficient assembly of Sm-class ribonucleoproteins. Proc Natl Acad Sci U S A. 2005;102:17372-7 pubmed
    ..Collectively, our results identify a previously uncharacterized function for Gemin3 and Gemin4 in Sm core assembly and correlate the activity of this pathway with SMA. ..
  2. Gonsalvez G, Tian L, Ospina J, Boisvert F, Lamond A, Matera A. Two distinct arginine methyltransferases are required for biogenesis of Sm-class ribonucleoproteins. J Cell Biol. 2007;178:733-40 pubmed
    b>Small nuclear ribonucleoproteins (snRNPs) are core components of the spliceosome. The U1, U2, U4, and U5 snRNPs each contain a common set of seven Sm proteins...
  3. Fierro Monti I, Mohammed S, Matthiesen R, Santoro R, Burns J, Williams D, et al. Quantitative proteomics identifies Gemin5, a scaffolding protein involved in ribonucleoprotein assembly, as a novel partner for eukaryotic initiation factor 4E. J Proteome Res. 2006;5:1367-78 pubmed
    ..Our results demonstrate that our quantitative proteomic strategy can be applied to the identification and quantitation of protein complex components in human cells grown under different conditions. ..
  4. Ali G, Prasad K, Hanumappa M, Reddy A. Analyses of in vivo interaction and mobility of two spliceosomal proteins using FRAP and BiFC. PLoS ONE. 2008;3:e1953 pubmed publisher
    ..Furthermore, although it appears that U1-70K moves by diffusion its mobility is regulated by phosphorylation and transcription. ..
  5. Kuhn A, van Santen M, Schwienhorst A, Urlaub H, Luhrmann R. Stalling of spliceosome assembly at distinct stages by small-molecule inhibitors of protein acetylation and deacetylation. RNA. 2009;15:153-75 pubmed publisher
    ..This suggests that the stalled complexes represent hitherto unobserved intermediates of spliceosome assembly. ..
  6. Vertegaal A, Ogg S, Jaffray E, Rodriguez M, Hay R, Andersen J, et al. A proteomic study of SUMO-2 target proteins. J Biol Chem. 2004;279:33791-8 pubmed
    ..SART1 and heterogeneous nuclear RNP M were both shown to be genuine SUMO targets, confirming the validity of the approach. ..
  7. Barboric M, Lenasi T, Chen H, Johansen E, Guo S, Peterlin B. 7SK snRNP/P-TEFb couples transcription elongation with alternative splicing and is essential for vertebrate development. Proc Natl Acad Sci U S A. 2009;106:7798-803 pubmed publisher
    ..These findings reveal a key role for P-TEFb in coupling transcription elongation with alternative splicing, and suggest that maintaining core 7SK snRNP is essential for vertebrate development. ..
  8. Gonsalvez G, Rajendra T, Tian L, Matera A. The Sm-protein methyltransferase, dart5, is essential for germ-cell specification and maintenance. Curr Biol. 2006;16:1077-89 pubmed
    ..The precise function of this posttranslational modification in the biogenesis of small nuclear ribonucleoproteins (snRNPs) and pre-mRNA splicing remains largely uncharacterized...
  9. Byers S, Price J, Cooper J, Li Q, Price D. HEXIM2, a HEXIM1-related protein, regulates positive transcription elongation factor b through association with 7SK. J Biol Chem. 2005;280:16360-7 pubmed
    ..Our results provide strong evidence that HEXIM2 is a regulator of P-TEFb function. Furthermore, our results support the idea that the utilization of HEXIM1 or HEXIM2 to bind and inhibit P-TEFb can be differentially regulated in vivo. ..
  10. Miranda T, Khusial P, Cook J, Lee J, Gunderson S, Pestka S, et al. Spliceosome Sm proteins D1, D3, and B/B' are asymmetrically dimethylated at arginine residues in the nucleus. Biochem Biophys Res Commun. 2004;323:382-7 pubmed
    ..These results suggest that the activity responsible for the formation of asymmetric dimethylated arginine residues in Sm proteins is either PRMT5 or a protein associated with it in the immunoprecipitated complex. ..
  11. Wang C, Meier U. Architecture and assembly of mammalian H/ACA small nucleolar and telomerase ribonucleoproteins. EMBO J. 2004;23:1857-67 pubmed
    ..Nonetheless, functional H/ACA snoRNPs assembled in cytosolic extracts are stable and do not exchange their RNA components, suggesting that new particle formation requires de novo synthesis. ..
  12. Wang P, Palfi Z, Preusser C, Lücke S, Lane W, Kambach C, et al. Sm core variation in spliceosomal small nuclear ribonucleoproteins from Trypanosoma brucei. EMBO J. 2006;25:4513-23 pubmed
    Messenger RNA processing in trypanosomes by cis and trans splicing requires spliceosomal small nuclear ribonucleoproteins (snRNPs) U1, U2, U4/U6, and U5, as well as the spliced leader (SL) RNP...
  13. Ma Y, Dostie J, Dreyfuss G, Van Duyne G. The Gemin6-Gemin7 heterodimer from the survival of motor neurons complex has an Sm protein-like structure. Structure. 2005;13:883-92 pubmed
    ..quot; The SMN complex functions as an assembly machine for small nuclear ribonucleoproteins (snRNPs)-the major components of the spliceosome...
  14. Spiller M, Boon K, Reijns M, Beggs J. The Lsm2-8 complex determines nuclear localization of the spliceosomal U6 snRNA. Nucleic Acids Res. 2007;35:923-9 pubmed
    ..La protein, which binds only transiently to the nascent U6 transcript, has a smaller, apparently indirect, effect on U6 localization that is compatible with its proposed role as a chaperone in facilitating U6 snRNP assembly. ..
  15. Stanek D, Pridalová Hnilicová J, Novotny I, Huranová M, Blažíková M, Wen X, et al. Spliceosomal small nuclear ribonucleoprotein particles repeatedly cycle through Cajal bodies. Mol Biol Cell. 2008;19:2534-43 pubmed publisher
    ..Together, the data show that particular phases of the spliceosome cycle are compartmentalized in living cells, with reassembly of the tri-snRNP occurring in CBs. ..
  16. Grimmler M, Bauer L, Nousiainen M, Körner R, Meister G, Fischer U. Phosphorylation regulates the activity of the SMN complex during assembly of spliceosomal U snRNPs. EMBO Rep. 2005;6:70-6 pubmed
    The assembly of spliceosomal U-rich small nuclear ribonucleoproteins (U snRNPs) is an ATP-dependent process mediated by the coordinated action of the SMN and the PRMT5 complex...
  17. Winkler C, Eggert C, Gradl D, Meister G, Giegerich M, Wedlich D, et al. Reduced U snRNP assembly causes motor axon degeneration in an animal model for spinal muscular atrophy. Genes Dev. 2005;19:2320-30 pubmed
    ..These findings suggest that motoneuron degeneration in SMA patients is a direct consequence of impaired production of U snRNPs. ..
  18. Van Herreweghe E, Egloff S, Goiffon I, Jady B, Froment C, Monsarrat B, et al. Dynamic remodelling of human 7SK snRNP controls the nuclear level of active P-TEFb. EMBO J. 2007;26:3570-80 pubmed
    ..Thus, we propose that the nuclear level of active P-TEFb is controlled by dynamic and reversible remodelling of 7SK snRNP. ..
  19. Czudnochowski N, Vollmuth F, Baumann S, Vogel Bachmayr K, Geyer M. Specificity of Hexim1 and Hexim2 complex formation with cyclin T1/T2, importin alpha and 7SK snRNA. J Mol Biol. 2010;395:28-41 pubmed publisher
    ..These results provide the molecular basis for the generation of a core complex for the inhibition of P-TEFb. ..
  20. Battle D, Kasim M, Yong J, Lotti F, Lau C, Mouaikel J, et al. The SMN complex: an assembly machine for RNPs. Cold Spring Harb Symp Quant Biol. 2006;71:313-20 pubmed
    In eukaryotic cells, the biogenesis of spliceosomal small nuclear ribonucleoproteins (snRNPs) and likely other RNPs is mediated by an assemblyosome, the survival of motor neurons (SMN) complex...
  21. Kolb S, Battle D, Dreyfuss G. Molecular functions of the SMN complex. J Child Neurol. 2007;22:990-4 pubmed
    The SMN complex is essential for the biogenesis of spliceosomal small nuclear ribonucleoproteins and likely functions in the assembly, metabolism, and transport of a diverse number of other ribonucleoproteins...
  22. Golembe T, Yong J, Dreyfuss G. Specific sequence features, recognized by the SMN complex, identify snRNAs and determine their fate as snRNPs. Mol Cell Biol. 2005;25:10989-1004 pubmed
    The survival of motor neurons (SMN) complex is essential for the biogenesis of spliceosomal small nuclear ribonucleoproteins (snRNPs) as it binds to and delivers Sm proteins for assembly of Sm cores on the abundant small nuclear RNAs (..
  23. Khusial P, Plaag R, Zieve G. LSm proteins form heptameric rings that bind to RNA via repeating motifs. Trends Biochem Sci. 2005;30:522-8 pubmed
    ..The two different rings that transiently bind to RNAs and, thereby, assist in the degradation of mRNA in the cytoplasm and the maturation of a wide spectrum of RNAs in the nucleus are called LSm rings. ..
  24. Schleiss M, Bernstein D, Passo M, Parker S, Meric C, Verdier F, et al. Lack of induction of autoantibody responses following immunization with cytomegalovirus (CMV) glycoprotein B (gB) in healthy CMV-seronegative subjects. Vaccine. 2004;23:687-92 pubmed
    ..These data reinforce the favorable safety profile of CMV gB vaccines. ..
  25. Lorkovic Z, Lopato S, Pexa M, Lehner R, Barta A. Interactions of Arabidopsis RS domain containing cyclophilins with SR proteins and U1 and U11 small nuclear ribonucleoprotein-specific proteins suggest their involvement in pre-mRNA Splicing. J Biol Chem. 2004;279:33890-8 pubmed
    ..Alternatively, binding of CypRS64 to proteins important for 5' splice site recognition suggests its involvement in the dynamics of spliceosome assembly. ..
  26. Szewczak L, Gabrielsen J, DeGregorio S, Strobel S, Steitz J. Molecular basis for RNA kink-turn recognition by the h15.5K small RNP protein. RNA. 2005;11:1407-19 pubmed
    ..An intramolecular RNA-RNA contact via a 2'-hydroxyl may supercede a putative Type I A-minor interaction in stabilizing the RNA-protein complex. ..
  27. Zaric B, Chami M, Remigy H, Engel A, Ballmer Hofer K, Winkler F, et al. Reconstitution of two recombinant LSm protein complexes reveals aspects of their architecture, assembly, and function. J Biol Chem. 2005;280:16066-75 pubmed
    ..Our in vitro reconstitution results illustrate likely features of the LSm complex assembly pathway. We prove the complexes to be functional both in an RNA bandshift and an in vivo cellular transport assay. ..
  28. Liu J, Gall J. U bodies are cytoplasmic structures that contain uridine-rich small nuclear ribonucleoproteins and associate with P bodies. Proc Natl Acad Sci U S A. 2007;104:11655-9 pubmed
    Uridine-rich small nuclear ribonucleoproteins (U snRNPs) are involved in key steps of pre-mRNA processing in the nucleus of eukaryotic cells...
  29. Turner I, Norman C, Churcher M, Newman A. Roles of the U5 snRNP in spliceosome dynamics and catalysis. Biochem Soc Trans. 2004;32:928-31 pubmed
    ..In the present review, we summarize our current understanding of the role played by the protein components of the U5 snRNP in pre-mRNA splicing, which include some of the largest and most highly conserved nuclear proteins. ..
  30. Yik J, Chen R, Pezda A, Zhou Q. Compensatory contributions of HEXIM1 and HEXIM2 in maintaining the balance of active and inactive positive transcription elongation factor b complexes for control of transcription. J Biol Chem. 2005;280:16368-76 pubmed
    ..Our results demonstrate that there is a tightly regulated cellular process to maintain the balance between active and inactive P-TEFb complexes, which controls global transcription as well as cell growth and differentiation. ..
  31. Tritschler F, Eulalio A, Truffault V, Hartmann M, Helms S, Schmidt S, et al. A divergent Sm fold in EDC3 proteins mediates DCP1 binding and P-body targeting. Mol Cell Biol. 2007;27:8600-11 pubmed
    ..The conservation of surface and of critical structural residues indicates that LSm domains in EDC3 proteins adopt a similar fold that has separable novel functions that are absent in canonical (L)Sm proteins...
  32. Strasser A, Dickmanns A, Luhrmann R, Ficner R. Structural basis for m3G-cap-mediated nuclear import of spliceosomal UsnRNPs by snurportin1. EMBO J. 2005;24:2235-43 pubmed
    ..The critical role of this tryptophan and as well of a tryptophan continuing the RNA base stack was confirmed by nuclear import assays and cap-binding activity tests using several snurportin1 mutants. ..
  33. Contreras X, Barboric M, Lenasi T, Peterlin B. HMBA releases P-TEFb from HEXIM1 and 7SK snRNA via PI3K/Akt and activates HIV transcription. PLoS Pathog. 2007;3:1459-69 pubmed
    ..Thus, our studies reveal how HIV transcription is induced by HMBA and suggest how modifications in the equilibrium between active and inactive P-TEFb could contribute to cell differentiation. ..
  34. Schellenberg M, Edwards R, Ritchie D, Kent O, Golas M, Stark H, et al. Crystal structure of a core spliceosomal protein interface. Proc Natl Acad Sci U S A. 2006;103:1266-71 pubmed
    ..SF3b155 presents a noncanonical surface for RNA recognition at the heart of the mammalian spliceosome. ..
  35. Patel S, Novikova N, Bellini M. Splicing-independent recruitment of spliceosomal small nuclear RNPs to nascent RNA polymerase II transcripts. J Cell Biol. 2007;178:937-49 pubmed
    ..Collectively, these data indicate that the recruitment of snRNPs to nascent transcripts and the assembly of the spliceosome are uncoupled events. ..
  36. Landers M, Bancescu D, Le Meur E, Rougeulle C, Glatt Deeley H, Brannan C, et al. Regulation of the large (approximately 1000 kb) imprinted murine Ube3a antisense transcript by alternative exons upstream of Snurf/Snrpn. Nucleic Acids Res. 2004;32:3480-92 pubmed
  37. Barboric M, Yik J, Czudnochowski N, Yang Z, Chen R, Contreras X, et al. Tat competes with HEXIM1 to increase the active pool of P-TEFb for HIV-1 transcription. Nucleic Acids Res. 2007;35:2003-12 pubmed
    ..All these data are consistent with the model that Tat not only recruits but also increases the active pool of P-TEFb for efficient HIV-1 transcription. ..
  38. Patel S, Bellini M. The assembly of a spliceosomal small nuclear ribonucleoprotein particle. Nucleic Acids Res. 2008;36:6482-93 pubmed publisher
    ..The aim of this review is, then, to briefly outline the structure of snRNPs and to synthesize new and exciting developments in the snRNP biogenesis pathways. ..
  39. Carissimi C, Baccon J, Straccia M, Chiarella P, Maiolica A, Sawyer A, et al. Unrip is a component of SMN complexes active in snRNP assembly. FEBS Lett. 2005;579:2348-54 pubmed
    ..interacts with Sm proteins and snRNAs to carry out the assembly of these components into spliceosomal small nuclear ribonucleoproteins (snRNPs)...
  40. Görnemann J, Kotovic K, Hujer K, Neugebauer K. Cotranscriptional spliceosome assembly occurs in a stepwise fashion and requires the cap binding complex. Mol Cell. 2005;19:53-63 pubmed
    ..Thus, the demonstration of an essential link between CBC and spliceosome assembly in vivo indicates that 5' end capping couples pre-mRNA splicing to transcription. ..
  41. Schumperli D, Pillai R. The special Sm core structure of the U7 snRNP: far-reaching significance of a small nuclear ribonucleoprotein. Cell Mol Life Sci. 2004;61:2560-70 pubmed
  42. Zhang Z, Lotti F, Dittmar K, Younis I, Wan L, Kasim M, et al. SMN deficiency causes tissue-specific perturbations in the repertoire of snRNAs and widespread defects in splicing. Cell. 2008;133:585-600 pubmed publisher
    ..These findings reveal a key role for the SMN complex in RNA metabolism and in splicing regulation and indicate that SMA is a general splicing disease that is not restricted to motor neurons. ..
  43. Avila A, Burnett B, Taye A, Gabanella F, Knight M, Hartenstein P, et al. Trichostatin A increases SMN expression and survival in a mouse model of spinal muscular atrophy. J Clin Invest. 2007;117:659-71 pubmed
    ..These results indicate that the hydroxamic acid class of HDAC inhibitors activates SMN2 gene expression in vivo and has an ameliorating effect on the SMA disease phenotype when administered after disease onset. ..
  44. Krueger B, Jeronimo C, Roy B, Bouchard A, Barrandon C, Byers S, et al. LARP7 is a stable component of the 7SK snRNP while P-TEFb, HEXIM1 and hnRNP A1 are reversibly associated. Nucleic Acids Res. 2008;36:2219-29 pubmed publisher
    ..Our studies have identified LARP7 as a 7SK-binding protein and suggest that free P-TEFb levels are determined by a balance between release from the large form and reduction of total P-TEFb. ..
  45. Otter S, Grimmler M, Neuenkirchen N, Chari A, Sickmann A, Fischer U. A comprehensive interaction map of the human survival of motor neuron (SMN) complex. J Biol Chem. 2007;282:5825-33 pubmed
    ..Collectively, the data presented here provide a basis for the detailed mechanistic and structural analysis of the assembly machinery of U snRNPs. ..
  46. Kühn Hölsken E, Dybkov O, Sander B, Luhrmann R, Urlaub H. Improved identification of enriched peptide RNA cross-links from ribonucleoprotein particles (RNPs) by mass spectrometry. Nucleic Acids Res. 2007;35:e95 pubmed
    ..Applying our approach to a partial complex of U2 snRNP allowed us to identify the contact site between the U2 snRNP-specific protein p14/SF3b14a and the branch-site interacting region (BSiR) of U2 snRNA. ..
  47. Verdone L, Galardi S, Page D, Beggs J. Lsm proteins promote regeneration of pre-mRNA splicing activity. Curr Biol. 2004;14:1487-91 pubmed
    ..Such a function could explain the involvement of Lsm proteins in a wide variety of RNA processing pathways. ..
  48. Nielsen J, B ggild A, Andersen C, Nielsen G, Boysen A, Brodersen D, et al. An Hfq-like protein in archaea: crystal structure and functional characterization of the Sm protein from Methanococcus jannaschii. RNA. 2007;13:2213-23 pubmed publisher
    ..Functional analysis reveals that Escherichia coli and M. jannaschii Hfqs display very similar biochemical and biological properties. It thus appears that the archaeal and bacterial Hfq proteins are largely functionally interchangeable...
  49. Gonsalvez G, Praveen K, Hicks A, Tian L, Matera A. Sm protein methylation is dispensable for snRNP assembly in Drosophila melanogaster. RNA. 2008;14:878-87 pubmed publisher
    ..In contrast, dart5 mutants displayed a strong synthetic lethal phenotype in the presence of a hypomorphic Smn mutation. We therefore conclude that dart5 is required for viability when SMN is limiting. ..
  50. Cioce M, Lamond A. Cajal bodies: a long history of discovery. Annu Rev Cell Dev Biol. 2005;21:105-31 pubmed
    ..We speculate on the relationship between CB function and molecular disease...
  51. Dieker J, Van Bavel C, Riemekasten G, Berden J, van der Vlag J. The binding of lupus-derived autoantibodies to the C-terminal peptide (83-119) of the major SmD1 autoantigen can be mediated by double-stranded DNA and nucleosomes. Ann Rheum Dis. 2006;65:1525-8 pubmed
  52. Kelly K, Zhuang H, Nacionales D, Scumpia P, Lyons R, Akaogi J, et al. "Endogenous adjuvant" activity of the RNA components of lupus autoantigens Sm/RNP and Ro 60. Arthritis Rheum. 2006;54:1557-67 pubmed
  53. Lemm I, Girard C, Kuhn A, Watkins N, Schneider M, Bordonné R, et al. Ongoing U snRNP biogenesis is required for the integrity of Cajal bodies. Mol Biol Cell. 2006;17:3221-31 pubmed
    Cajal bodies (CBs) have been implicated in the nuclear phase of the biogenesis of spliceosomal U small nuclear ribonucleoproteins (U snRNPs)...
  54. Schultz A, Nottrott S, Watkins N, Luhrmann R. Protein-protein and protein-RNA contacts both contribute to the 15.5K-mediated assembly of the U4/U6 snRNP and the box C/D snoRNPs. Mol Cell Biol. 2006;26:5146-54 pubmed
    ..5K. In conclusion, our data suggest that the formation of each RNP involves the direct recognition of specific elements in both 15.5K protein and the specific RNA. ..
  55. Blencowe B. Alternative splicing: new insights from global analyses. Cell. 2006;126:37-47 pubmed
    ..Recent progress in these areas is summarized in this review. ..
  56. Cojocaru V, Nottrott S, Klement R, Jovin T. The snRNP 15.5K protein folds its cognate K-turn RNA: a combined theoretical and biochemical study. RNA. 2005;11:197-209 pubmed
    ..Based on these observations, we propose a protein-assisted RNA folding mechanism in which the RNA intrinsic flexibility functions as a catalyst. ..
  57. Battle D, Lau C, Wan L, Deng H, Lotti F, Dreyfuss G. The Gemin5 protein of the SMN complex identifies snRNAs. Mol Cell. 2006;23:273-9 pubmed
    ..Gemin5 therefore functions as the factor that allows the SMN complex to distinguish snRNAs from other cellular RNAs for snRNP biogenesis. ..
  58. Rollenhagen C, Pante N. Nuclear import of spliceosomal snRNPs. Can J Physiol Pharmacol. 2006;84:367-76 pubmed
    Uridine-rich small nuclear ribonucleoproteins (U snRNPs) are the building units of the spliceosome. These RNA and protein complexes assemble in the cytoplasm...
  59. Beggs J. Lsm proteins and RNA processing. Biochem Soc Trans. 2005;33:433-8 pubmed
    ..This article reviews the properties of the Sm and Lsm proteins and structurally and functionally related proteins in archaea and eubacteria. ..
  60. Mahler M, Fritzler M, Bluthner M. Identification of a SmD3 epitope with a single symmetrical dimethylation of an arginine residue as a specific target of a subpopulation of anti-Sm antibodies. Arthritis Res Ther. 2005;7:R19-29 pubmed
    ..Thus, anti-SMP detection using ELISA represents a new serological marker with which to diagnose and discriminate between systemic autoimmune disorders. ..
  61. Matera A, Terns R, Terns M. Non-coding RNAs: lessons from the small nuclear and small nucleolar RNAs. Nat Rev Mol Cell Biol. 2007;8:209-20 pubmed publisher
    ..The small nuclear and small nucleolar RNPs are two well studied classes of ncRNPs with elaborate assembly and trafficking pathways that provide paradigms for understanding the biogenesis of other ncRNPs. ..
  62. Tardiff D, Rosbash M. Arrested yeast splicing complexes indicate stepwise snRNP recruitment during in vivo spliceosome assembly. RNA. 2006;12:968-79 pubmed
    ..These complexes have implications for the steady-state distribution of snRNPs within nuclei and also reinforce the stepwise recruitment of U1, U2, and the tri-snRNP during in vivo spliceosome assembly. ..
  63. Tritschler F, Eulalio A, Helms S, Schmidt S, Coles M, Weichenrieder O, et al. Similar modes of interaction enable Trailer Hitch and EDC3 to associate with DCP1 and Me31B in distinct protein complexes. Mol Cell Biol. 2008;28:6695-708 pubmed publisher
    ..Together with previous studies, our results show that Tral and EDC3 are structurally related and use a similar mode to associate with common partners in distinct protein complexes. ..
  64. Liu J, Murphy C, Buszczak M, Clatterbuck S, Goodman R, Gall J. The Drosophila melanogaster Cajal body. J Cell Biol. 2006;172:875-84 pubmed
    ..melanogaster. The identification of these nuclear bodies now permits a broad range of questions to be asked about CB structure and function in a genetically tractable organism. ..
  65. Li Q, Price J, Byers S, Cheng D, Peng J, Price D. Analysis of the large inactive P-TEFb complex indicates that it contains one 7SK molecule, a dimer of HEXIM1 or HEXIM2, and two P-TEFb molecules containing Cdk9 phosphorylated at threonine 186. J Biol Chem. 2005;280:28819-26 pubmed
    ..HEXIM complex. A model illustrates what is currently known about how HEXIM proteins, 7SK, and P-TEFb assemble to maintain an activated kinase in a readily available, but inactive form. ..
  66. Clery A, Senty Ségault V, Leclerc F, Raué H, Branlant C. Analysis of sequence and structural features that identify the B/C motif of U3 small nucleolar RNA as the recognition site for the Snu13p-Rrp9p protein pair. Mol Cell Biol. 2007;27:1191-206 pubmed
    ..They bring important information to understand how different K-turn motifs can recruit different sets of proteins after Snu13p association. ..
  67. He N, Jahchan N, Hong E, Li Q, Bayfield M, Maraia R, et al. A La-related protein modulates 7SK snRNP integrity to suppress P-TEFb-dependent transcriptional elongation and tumorigenesis. Mol Cell. 2008;29:588-99 pubmed publisher
    ..Through PIP7S modulation of P-TEFb, our data thus link a general elongation factor to growth control and tumorigenesis. ..
  68. Chen R, Liu M, Li H, Xue Y, Ramey W, He N, et al. PP2B and PP1alpha cooperatively disrupt 7SK snRNP to release P-TEFb for transcription in response to Ca2+ signaling. Genes Dev. 2008;22:1356-68 pubmed publisher
    ..Thus, through cooperatively dephosphorylating Cdk9 in response to Ca2+ signaling, PP2B and PP1alpha alter the P-TEFb functional equilibrium through releasing P-TEFb from 7SK snRNP for transcription. ..
  69. Girard C, Neel H, Bertrand E, Bordonné R. Depletion of SMN by RNA interference in HeLa cells induces defects in Cajal body formation. Nucleic Acids Res. 2006;34:2925-32 pubmed
    ..Because Cajal bodies represent the location in which snRNPs undergo 2'-O-methylation and pseudouridylation, our results raise the possibility that SMN depletion might give rise to a defect in the snRNA modification process...
  70. Neuenkirchen N, Chari A, Fischer U. Deciphering the assembly pathway of Sm-class U snRNPs. FEBS Lett. 2008;582:1997-2003 pubmed publisher
    The assembly of the Sm-class of uridine-rich small nuclear ribonucleoproteins (U snRNPs), albeit spontaneous in vitro, has recently been shown to be dependent on the aid of a large number of assisting factors in vivo...
  71. Spiller M, Reijns M, Beggs J. Requirements for nuclear localization of the Lsm2-8p complex and competition between nuclear and cytoplasmic Lsm complexes. J Cell Sci. 2007;120:4310-20 pubmed
    ..A shift of Lsm proteins from the nucleus to the cytoplasm under stress conditions indicates that this competition is biologically significant. ..
  72. Carrel T, McWhorter M, Workman E, Zhang H, Wolstencroft E, Lorson C, et al. Survival motor neuron function in motor axons is independent of functions required for small nuclear ribonucleoprotein biogenesis. J Neurosci. 2006;26:11014-22 pubmed
    ..Thus, we have dissociated the snRNP function of SMN from its function in motor axons. These data indicate that SMN has a novel function in motor axons that is relevant to SMA and is independent of snRNP biosynthesis. ..
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    ..These data are consistent with the notion that in fission yeast phosphorylation of Prp1 by Prp4 kinase is involved in the activation of pre-catalytic spliceosomes. ..
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    ..U4/U6 snRNP in CBs. Thus, while some U4/U6 snRNP assembly can occur in the nucleoplasm, these data provide evidence that SART3.U6 snRNPs form in the nucleoplasm and translocate to CBs where U4/U6 snRNP assembly occurs...
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    ..The features this structure reveals provide new insight into the global architecture of the native splicing machine. ..
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    ..with Gemins2-8 and unrip proteins form a macromolecular complex that functions in the assembly of small nuclear ribonucleoproteins (snRNPs) of both the major and the minor splicing pathways...
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    ..Concurrently, the P-TEFb equilibrium was shifted overwhelmingly toward the 7SK snRNP side. Together, these data link the P-TEFb equilibrium to the intracellular transcriptional demand and proliferative/differentiated states of cells. ..
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    ..Thus a serum test for autoantibodies in toxocarosis patients might be a valuable gatekeeper assay for the decision for or against anti-inflammatory treatment. ..
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    ..six other proteins, named Gemins2-7, and plays an essential role in the assembly of the spliceosomal small nuclear ribonucleoproteins (snRNPs)...