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. 1992 Jul 1;118(1):11–21. doi: 10.1083/jcb.118.1.11

Intracellular distribution of the U1A protein depends on active transport and nuclear binding to U1 snRNA

PMCID: PMC2289521  PMID: 1618898

Abstract

Nuclear transport of the U1 snRNP-specific protein U1A has been examined. U1A moves to the nucleus by an active process which is independent of interaction with U1 snRNA. Nuclear localization requires an unusually large sequence element situated between amino acids 94 and 204 of the protein. U1A transport is not unidirectional. The protein shuttles between nucleus and cytoplasm. At equilibrium, the concentration of the protein in the nucleus and cytoplasm is not, however, determined solely by transport rates, but can be perturbed by introducing RNA sequences that can specifically bind U1A in either the nuclear or cytoplasmic compartment. Thus, U1A represents a novel class of protein which shuttles between cytoplasm and nucleus and whose intracellular distribution can be altered by the number of free binding sites for the protein present in the cytoplasm or the nucleus.

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Selected References

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  1. Boelens W., Scherly D., Jansen E. J., Kolen K., Mattaj I. W., van Venrooij W. J. Analysis of in vitro binding of U1-A protein mutants to U1 snRNA. Nucleic Acids Res. 1991 Sep 11;19(17):4611–4618. doi: 10.1093/nar/19.17.4611. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Borer R. A., Lehner C. F., Eppenberger H. M., Nigg E. A. Major nucleolar proteins shuttle between nucleus and cytoplasm. Cell. 1989 Feb 10;56(3):379–390. doi: 10.1016/0092-8674(89)90241-9. [DOI] [PubMed] [Google Scholar]
  3. Breeuwer M., Goldfarb D. S. Facilitated nuclear transport of histone H1 and other small nucleophilic proteins. Cell. 1990 Mar 23;60(6):999–1008. doi: 10.1016/0092-8674(90)90348-i. [DOI] [PubMed] [Google Scholar]
  4. Bujard H., Gentz R., Lanzer M., Stueber D., Mueller M., Ibrahimi I., Haeuptle M. T., Dobberstein B. A T5 promoter-based transcription-translation system for the analysis of proteins in vitro and in vivo. Methods Enzymol. 1987;155:416–433. doi: 10.1016/0076-6879(87)55028-5. [DOI] [PubMed] [Google Scholar]
  5. Dabauvalle M. C., Schulz B., Scheer U., Peters R. Inhibition of nuclear accumulation of karyophilic proteins in living cells by microinjection of the lectin wheat germ agglutinin. Exp Cell Res. 1988 Jan;174(1):291–296. doi: 10.1016/0014-4827(88)90163-2. [DOI] [PubMed] [Google Scholar]
  6. Dingwall C., Sharnick S. V., Laskey R. A. A polypeptide domain that specifies migration of nucleoplasmin into the nucleus. Cell. 1982 Sep;30(2):449–458. doi: 10.1016/0092-8674(82)90242-2. [DOI] [PubMed] [Google Scholar]
  7. Dumont J. N. Oogenesis in Xenopus laevis (Daudin). I. Stages of oocyte development in laboratory maintained animals. J Morphol. 1972 Feb;136(2):153–179. doi: 10.1002/jmor.1051360203. [DOI] [PubMed] [Google Scholar]
  8. Eliceiri G. L. Short-lived, small RNAs in the cytoplasm of HeLa cells. Cell. 1974 Sep;3(1):11–14. doi: 10.1016/0092-8674(74)90031-2. [DOI] [PubMed] [Google Scholar]
  9. Feeney R. J., Sauterer R. A., Feeney J. L., Zieve G. W. Cytoplasmic assembly and nuclear accumulation of mature small nuclear ribonucleoprotein particles. J Biol Chem. 1989 Apr 5;264(10):5776–5783. [PubMed] [Google Scholar]
  10. Feeney R. J., Zieve G. W. Nuclear exchange of the U1 and U2 snRNP-specific proteins. J Cell Biol. 1990 Apr;110(4):871–881. doi: 10.1083/jcb.110.4.871. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Finlay D. R., Forbes D. J. Reconstitution of biochemically altered nuclear pores: transport can be eliminated and restored. Cell. 1990 Jan 12;60(1):17–29. doi: 10.1016/0092-8674(90)90712-n. [DOI] [PubMed] [Google Scholar]
  12. Finlay D. R., Newmeyer D. D., Price T. M., Forbes D. J. Inhibition of in vitro nuclear transport by a lectin that binds to nuclear pores. J Cell Biol. 1987 Feb;104(2):189–200. doi: 10.1083/jcb.104.2.189. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Fischer U., Darzynkiewicz E., Tahara S. M., Dathan N. A., Lührmann R., Mattaj I. W. Diversity in the signals required for nuclear accumulation of U snRNPs and variety in the pathways of nuclear transport. J Cell Biol. 1991 May;113(4):705–714. doi: 10.1083/jcb.113.4.705. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Fischer U., Lührmann R. An essential signaling role for the m3G cap in the transport of U1 snRNP to the nucleus. Science. 1990 Aug 17;249(4970):786–790. doi: 10.1126/science.2143847. [DOI] [PubMed] [Google Scholar]
  15. Gaillard C., Strauss F. Ethanol precipitation of DNA with linear polyacrylamide as carrier. Nucleic Acids Res. 1990 Jan 25;18(2):378–378. doi: 10.1093/nar/18.2.378. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Garcia-Bustos J., Heitman J., Hall M. N. Nuclear protein localization. Biochim Biophys Acta. 1991 Mar 7;1071(1):83–101. doi: 10.1016/0304-4157(91)90013-m. [DOI] [PubMed] [Google Scholar]
  17. Goldfarb D. S. Nuclear transport. Curr Opin Cell Biol. 1989 Jun;1(3):441–446. doi: 10.1016/0955-0674(89)90003-3. [DOI] [PubMed] [Google Scholar]
  18. Goldfarb D. S. Shuttling proteins go both ways. Curr Biol. 1991 Aug;1(4):212–214. doi: 10.1016/0960-9822(91)90059-6. [DOI] [PubMed] [Google Scholar]
  19. Gurdon J. B. Injected nuclei in frog oocytes: fate, enlargement, and chromatin dispersal. J Embryol Exp Morphol. 1976 Dec;36(3):523–540. [PubMed] [Google Scholar]
  20. Hall M. N., Hereford L., Herskowitz I. Targeting of E. coli beta-galactosidase to the nucleus in yeast. Cell. 1984 Apr;36(4):1057–1065. doi: 10.1016/0092-8674(84)90055-2. [DOI] [PubMed] [Google Scholar]
  21. Hamm J., Darzynkiewicz E., Tahara S. M., Mattaj I. W. The trimethylguanosine cap structure of U1 snRNA is a component of a bipartite nuclear targeting signal. Cell. 1990 Aug 10;62(3):569–577. doi: 10.1016/0092-8674(90)90021-6. [DOI] [PubMed] [Google Scholar]
  22. Hamm J., Dathan N. A., Mattaj I. W. Functional analysis of mutant Xenopus U2 snRNAs. Cell. 1989 Oct 6;59(1):159–169. doi: 10.1016/0092-8674(89)90878-7. [DOI] [PubMed] [Google Scholar]
  23. Hamm J., Dathan N. A., Scherly D., Mattaj I. W. Multiple domains of U1 snRNA, including U1 specific protein binding sites, are required for splicing. EMBO J. 1990 Apr;9(4):1237–1244. doi: 10.1002/j.1460-2075.1990.tb08231.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Hamm J., Mattaj I. W. Monomethylated cap structures facilitate RNA export from the nucleus. Cell. 1990 Oct 5;63(1):109–118. doi: 10.1016/0092-8674(90)90292-m. [DOI] [PubMed] [Google Scholar]
  25. Heinrichs V., Bach M., Winkelmann G., Lührmann R. U1-specific protein C needed for efficient complex formation of U1 snRNP with a 5' splice site. Science. 1990 Jan 5;247(4938):69–72. doi: 10.1126/science.2136774. [DOI] [PubMed] [Google Scholar]
  26. Kalderon D., Roberts B. L., Richardson W. D., Smith A. E. A short amino acid sequence able to specify nuclear location. Cell. 1984 Dec;39(3 Pt 2):499–509. doi: 10.1016/0092-8674(84)90457-4. [DOI] [PubMed] [Google Scholar]
  27. Kleinschmidt J. A., Dingwall C., Maier G., Franke W. W. Molecular characterization of a karyophilic, histone-binding protein: cDNA cloning, amino acid sequence and expression of nuclear protein N1/N2 of Xenopus laevis. EMBO J. 1986 Dec 20;5(13):3547–3552. doi: 10.1002/j.1460-2075.1986.tb04681.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Krohne G., Waizenegger I., Höger T. H. The conserved carboxy-terminal cysteine of nuclear lamins is essential for lamin association with the nuclear envelope. J Cell Biol. 1989 Nov;109(5):2003–2011. doi: 10.1083/jcb.109.5.2003. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Lamond A. L. The trimethyl-guanosine cap is a nuclear targeting signal for snRNPs. Trends Biochem Sci. 1990 Dec;15(12):451–452. doi: 10.1016/0968-0004(90)90292-j. [DOI] [PubMed] [Google Scholar]
  30. Lanford R. E., Butel J. S. Construction and characterization of an SV40 mutant defective in nuclear transport of T antigen. Cell. 1984 Jul;37(3):801–813. doi: 10.1016/0092-8674(84)90415-x. [DOI] [PubMed] [Google Scholar]
  31. Lehmeier T., Foulaki K., Lührmann R. Evidence for three distinct D proteins, which react differentially with anti-Sm autoantibodies, in the cores of the major snRNPs U1, U2, U4/U6 and U5. Nucleic Acids Res. 1990 Nov 25;18(22):6475–6484. doi: 10.1093/nar/18.22.6475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Lerner E. A., Lerner M. R., Janeway C. A., Jr, Steitz J. A. Monoclonal antibodies to nucleic acid-containing cellular constituents: probes for molecular biology and autoimmune disease. Proc Natl Acad Sci U S A. 1981 May;78(5):2737–2741. doi: 10.1073/pnas.78.5.2737. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Lutz-Freyermuth C., Query C. C., Keene J. D. Quantitative determination that one of two potential RNA-binding domains of the A protein component of the U1 small nuclear ribonucleoprotein complex binds with high affinity to stem-loop II of U1 RNA. Proc Natl Acad Sci U S A. 1990 Aug;87(16):6393–6397. doi: 10.1073/pnas.87.16.6393. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Lührmann R., Kastner B., Bach M. Structure of spliceosomal snRNPs and their role in pre-mRNA splicing. Biochim Biophys Acta. 1990 Nov 30;1087(3):265–292. doi: 10.1016/0167-4781(90)90001-i. [DOI] [PubMed] [Google Scholar]
  35. Mandell R. B., Feldherr C. M. Identification of two HSP70-related Xenopus oocyte proteins that are capable of recycling across the nuclear envelope. J Cell Biol. 1990 Nov;111(5 Pt 1):1775–1783. doi: 10.1083/jcb.111.5.1775. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Mattaj I. W., De Robertis E. M. Nuclear segregation of U2 snRNA requires binding of specific snRNP proteins. Cell. 1985 Jan;40(1):111–118. doi: 10.1016/0092-8674(85)90314-9. [DOI] [PubMed] [Google Scholar]
  37. Mattaj I. W., Zeller R. Xenopus laevis U2 snRNA genes: tandemly repeated transcription units sharing 5' and 3' flanking homology with other RNA polymerase II transcribed genes. EMBO J. 1983;2(11):1883–1891. doi: 10.1002/j.1460-2075.1983.tb01675.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Michaud N., Goldfarb D. Microinjected U snRNAs are imported to oocyte nuclei via the nuclear pore complex by three distinguishable targeting pathways. J Cell Biol. 1992 Feb;116(4):851–861. doi: 10.1083/jcb.116.4.851. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Mount S. M., Pettersson I., Hinterberger M., Karmas A., Steitz J. A. The U1 small nuclear RNA-protein complex selectively binds a 5' splice site in vitro. Cell. 1983 Jun;33(2):509–518. doi: 10.1016/0092-8674(83)90432-4. [DOI] [PubMed] [Google Scholar]
  40. Nagai K., Oubridge C., Jessen T. H., Li J., Evans P. R. Crystal structure of the RNA-binding domain of the U1 small nuclear ribonucleoprotein A. Nature. 1990 Dec 6;348(6301):515–520. doi: 10.1038/348515a0. [DOI] [PubMed] [Google Scholar]
  41. Newmeyer D. D., Finlay D. R., Forbes D. J. In vitro transport of a fluorescent nuclear protein and exclusion of non-nuclear proteins. J Cell Biol. 1986 Dec;103(6 Pt 1):2091–2102. doi: 10.1083/jcb.103.6.2091. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Pan Z. Q., Prives C. Assembly of functional U1 and U2 human-amphibian hybrid snRNPs in Xenopus laevis oocytes. Science. 1988 Sep 9;241(4871):1328–1331. doi: 10.1126/science.2970672. [DOI] [PubMed] [Google Scholar]
  43. Pan Z. Q., Prives C. U2 snRNA sequences that bind U2-specific proteins are dispensable for the function of U2 snRNP in splicing. Genes Dev. 1989 Dec;3(12A):1887–1898. doi: 10.1101/gad.3.12a.1887. [DOI] [PubMed] [Google Scholar]
  44. Richardson W. D., Mills A. D., Dilworth S. M., Laskey R. A., Dingwall C. Nuclear protein migration involves two steps: rapid binding at the nuclear envelope followed by slower translocation through nuclear pores. Cell. 1988 Mar 11;52(5):655–664. doi: 10.1016/0092-8674(88)90403-5. [DOI] [PubMed] [Google Scholar]
  45. Rihs H. P., Peters R. Nuclear transport kinetics depend on phosphorylation-site-containing sequences flanking the karyophilic signal of the Simian virus 40 T-antigen. EMBO J. 1989 May;8(5):1479–1484. doi: 10.1002/j.1460-2075.1989.tb03531.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Robbins J., Dilworth S. M., Laskey R. A., Dingwall C. Two interdependent basic domains in nucleoplasmin nuclear targeting sequence: identification of a class of bipartite nuclear targeting sequence. Cell. 1991 Feb 8;64(3):615–623. doi: 10.1016/0092-8674(91)90245-t. [DOI] [PubMed] [Google Scholar]
  47. Scherly D., Boelens W., van Venrooij W. J., Dathan N. A., Hamm J., Mattaj I. W. Identification of the RNA binding segment of human U1 A protein and definition of its binding site on U1 snRNA. EMBO J. 1989 Dec 20;8(13):4163–4170. doi: 10.1002/j.1460-2075.1989.tb08601.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Silver P. A., Chiang A., Sadler I. Mutations that alter both localization and production of a yeast nuclear protein. Genes Dev. 1988 Jun;2(6):707–717. doi: 10.1101/gad.2.6.707. [DOI] [PubMed] [Google Scholar]
  49. Silver P. A. How proteins enter the nucleus. Cell. 1991 Feb 8;64(3):489–497. doi: 10.1016/0092-8674(91)90233-o. [DOI] [PubMed] [Google Scholar]
  50. Vankan P., McGuigan C., Mattaj I. W. Domains of U4 and U6 snRNAs required for snRNP assembly and splicing complementation in Xenopus oocytes. EMBO J. 1990 Oct;9(10):3397–3404. doi: 10.1002/j.1460-2075.1990.tb07541.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Zieve G. W., Sauterer R. A., Feeney R. J. Newly synthesized small nuclear RNAs appear transiently in the cytoplasm. J Mol Biol. 1988 Jan 20;199(2):259–267. doi: 10.1016/0022-2836(88)90312-9. [DOI] [PubMed] [Google Scholar]

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