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. 1995 Jun;1(4):407–417.

Sequential recognition of the pre-mRNA branch point by U2AF65 and a novel spliceosome-associated 28-kDa protein.

R K Gaur 1, J Valcárcel 1, M R Green 1
PMCID: PMC1482402  PMID: 7493318

Abstract

Splicing of pre-mRNAs occurs via a lariat intermediate in which an intronic adenosine, embedded within a branch point sequence, forms a 2',5'-phosphodiester bond (RNA branch) with the 5' end of the intron. How the branch point is recognized and activated remains largely unknown. Using site-specific photochemical cross-linking, we have identified two proteins that specifically interact with the branch point during the splicing reaction. U2AF65, an essential splicing factor that binds to the adjacent polypyrimidine tract, crosslinks to the branch point at the earliest stage of spliceosome formation in an ATP-independent manner. A novel 28-kDa protein, which is a constituent of the mature spliceosome, contacts the branch point after the first catalytic step. Our results indicate that the branch point is sequentially recognized by distinct splicing factors in the course of the splicing reaction.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Abmayr S. M., Reed R., Maniatis T. Identification of a functional mammalian spliceosome containing unspliced pre-mRNA. Proc Natl Acad Sci U S A. 1988 Oct;85(19):7216–7220. doi: 10.1073/pnas.85.19.7216. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Aebi M., Hornig H., Padgett R. A., Reiser J., Weissmann C. Sequence requirements for splicing of higher eukaryotic nuclear pre-mRNA. Cell. 1986 Nov 21;47(4):555–565. doi: 10.1016/0092-8674(86)90620-3. [DOI] [PubMed] [Google Scholar]
  3. Bergstrom D. E., Leonard N. J. Photoreaction of 4-thiouracil with cytosine. Relation to photoreactions in Escherichia coli transfer ribonucleic acids. Biochemistry. 1972 Jan 4;11(1):1–9. doi: 10.1021/bi00751a001. [DOI] [PubMed] [Google Scholar]
  4. Burgess S. M., Guthrie C. A mechanism to enhance mRNA splicing fidelity: the RNA-dependent ATPase Prp16 governs usage of a discard pathway for aberrant lariat intermediates. Cell. 1993 Jul 2;73(7):1377–1391. doi: 10.1016/0092-8674(93)90363-u. [DOI] [PubMed] [Google Scholar]
  5. Burgess S., Couto J. R., Guthrie C. A putative ATP binding protein influences the fidelity of branchpoint recognition in yeast splicing. Cell. 1990 Mar 9;60(5):705–717. doi: 10.1016/0092-8674(90)90086-t. [DOI] [PubMed] [Google Scholar]
  6. Champion-Arnaud P., Reed R. The prespliceosome components SAP 49 and SAP 145 interact in a complex implicated in tethering U2 snRNP to the branch site. Genes Dev. 1994 Aug 15;8(16):1974–1983. doi: 10.1101/gad.8.16.1974. [DOI] [PubMed] [Google Scholar]
  7. Cheng S. C., Abelson J. Spliceosome assembly in yeast. Genes Dev. 1987 Nov;1(9):1014–1027. doi: 10.1101/gad.1.9.1014. [DOI] [PubMed] [Google Scholar]
  8. Dignam J. D., Lebovitz R. M., Roeder R. G. Accurate transcription initiation by RNA polymerase II in a soluble extract from isolated mammalian nuclei. Nucleic Acids Res. 1983 Mar 11;11(5):1475–1489. doi: 10.1093/nar/11.5.1475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Fouser L. A., Friesen J. D. Mutations in a yeast intron demonstrate the importance of specific conserved nucleotides for the two stages of nuclear mRNA splicing. Cell. 1986 Apr 11;45(1):81–93. doi: 10.1016/0092-8674(86)90540-4. [DOI] [PubMed] [Google Scholar]
  10. Gaur R. K., Krupp G. Enzymatic RNA synthesis with deoxynucleoside 5'-O-(1-thiotriphosphates). FEBS Lett. 1993 Jan 2;315(1):56–60. doi: 10.1016/0014-5793(93)81132-j. [DOI] [PubMed] [Google Scholar]
  11. Green M. R. Biochemical mechanisms of constitutive and regulated pre-mRNA splicing. Annu Rev Cell Biol. 1991;7:559–599. doi: 10.1146/annurev.cb.07.110191.003015. [DOI] [PubMed] [Google Scholar]
  12. Guthrie C. Messenger RNA splicing in yeast: clues to why the spliceosome is a ribonucleoprotein. Science. 1991 Jul 12;253(5016):157–163. doi: 10.1126/science.1853200. [DOI] [PubMed] [Google Scholar]
  13. Habets W. J., Hoet M. H., De Jong B. A., Van der Kemp A., Van Venrooij W. J. Mapping of B cell epitopes on small nuclear ribonucleoproteins that react with human autoantibodies as well as with experimentally-induced mouse monoclonal antibodies. J Immunol. 1989 Oct 15;143(8):2560–2566. [PubMed] [Google Scholar]
  14. Horowitz D. S., Abelson J. A U5 small nuclear ribonucleoprotein particle protein involved only in the second step of pre-mRNA splicing in Saccharomyces cerevisiae. Mol Cell Biol. 1993 May;13(5):2959–2970. doi: 10.1128/mcb.13.5.2959. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Kandels-Lewis S., Séraphin B. Involvement of U6 snRNA in 5' splice site selection. Science. 1993 Dec 24;262(5142):2035–2039. doi: 10.1126/science.8266100. [DOI] [PubMed] [Google Scholar]
  16. Konarska M. M., Sharp P. A. Electrophoretic separation of complexes involved in the splicing of precursors to mRNAs. Cell. 1986 Sep 12;46(6):845–855. doi: 10.1016/0092-8674(86)90066-8. [DOI] [PubMed] [Google Scholar]
  17. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  18. Lamm G. M., Lamond A. I. Non-snRNP protein splicing factors. Biochim Biophys Acta. 1993 Jun 25;1173(3):247–265. doi: 10.1016/0167-4781(93)90122-t. [DOI] [PubMed] [Google Scholar]
  19. Lesser C. F., Guthrie C. Mutations in U6 snRNA that alter splice site specificity: implications for the active site. Science. 1993 Dec 24;262(5142):1982–1988. doi: 10.1126/science.8266093. [DOI] [PubMed] [Google Scholar]
  20. MacMillan A. M., Query C. C., Allerson C. R., Chen S., Verdine G. L., Sharp P. A. Dynamic association of proteins with the pre-mRNA branch region. Genes Dev. 1994 Dec 15;8(24):3008–3020. doi: 10.1101/gad.8.24.3008. [DOI] [PubMed] [Google Scholar]
  21. Madhani H. D., Guthrie C. A novel base-pairing interaction between U2 and U6 snRNAs suggests a mechanism for the catalytic activation of the spliceosome. Cell. 1992 Nov 27;71(5):803–817. doi: 10.1016/0092-8674(92)90556-r. [DOI] [PubMed] [Google Scholar]
  22. McPheeters D. S., Abelson J. Mutational analysis of the yeast U2 snRNA suggests a structural similarity to the catalytic core of group I introns. Cell. 1992 Nov 27;71(5):819–831. doi: 10.1016/0092-8674(92)90557-s. [DOI] [PubMed] [Google Scholar]
  23. Milligan J. F., Uhlenbeck O. C. Synthesis of small RNAs using T7 RNA polymerase. Methods Enzymol. 1989;180:51–62. doi: 10.1016/0076-6879(89)80091-6. [DOI] [PubMed] [Google Scholar]
  24. Moore M. J., Sharp P. A. Site-specific modification of pre-mRNA: the 2'-hydroxyl groups at the splice sites. Science. 1992 May 15;256(5059):992–997. doi: 10.1126/science.1589782. [DOI] [PubMed] [Google Scholar]
  25. Newman A. J., Lin R. J., Cheng S. C., Abelson J. Molecular consequences of specific intron mutations on yeast mRNA splicing in vivo and in vitro. Cell. 1985 Aug;42(1):335–344. doi: 10.1016/s0092-8674(85)80129-x. [DOI] [PubMed] [Google Scholar]
  26. Nilsen T. W. RNA-RNA interactions in the spliceosome: unraveling the ties that bind. Cell. 1994 Jul 15;78(1):1–4. doi: 10.1016/0092-8674(94)90563-0. [DOI] [PubMed] [Google Scholar]
  27. Padgett R. A., Konarska M. M., Grabowski P. J., Hardy S. F., Sharp P. A. Lariat RNA's as intermediates and products in the splicing of messenger RNA precursors. Science. 1984 Aug 31;225(4665):898–903. doi: 10.1126/science.6206566. [DOI] [PubMed] [Google Scholar]
  28. Parker R., Guthrie C. A point mutation in the conserved hexanucleotide at a yeast 5' splice junction uncouples recognition, cleavage, and ligation. Cell. 1985 May;41(1):107–118. doi: 10.1016/0092-8674(85)90065-0. [DOI] [PubMed] [Google Scholar]
  29. Parker R., Siliciano P. G., Guthrie C. Recognition of the TACTAAC box during mRNA splicing in yeast involves base pairing to the U2-like snRNA. Cell. 1987 Apr 24;49(2):229–239. doi: 10.1016/0092-8674(87)90564-2. [DOI] [PubMed] [Google Scholar]
  30. Pettersson I., Hinterberger M., Mimori T., Gottlieb E., Steitz J. A. The structure of mammalian small nuclear ribonucleoproteins. Identification of multiple protein components reactive with anti-(U1)ribonucleoprotein and anti-Sm autoantibodies. J Biol Chem. 1984 May 10;259(9):5907–5914. [PubMed] [Google Scholar]
  31. Query C. C., Moore M. J., Sharp P. A. Branch nucleophile selection in pre-mRNA splicing: evidence for the bulged duplex model. Genes Dev. 1994 Mar 1;8(5):587–597. doi: 10.1101/gad.8.5.587. [DOI] [PubMed] [Google Scholar]
  32. Reed R., Maniatis T. Intron sequences involved in lariat formation during pre-mRNA splicing. Cell. 1985 May;41(1):95–105. doi: 10.1016/0092-8674(85)90064-9. [DOI] [PubMed] [Google Scholar]
  33. Reuter R., Lehner C. F., Nigg E. A., Lührmann R. A monoclonal antibody specific for snRNPs U1 and U2. FEBS Lett. 1986 May 26;201(1):25–30. doi: 10.1016/0014-5793(86)80564-6. [DOI] [PubMed] [Google Scholar]
  34. Ruskin B., Krainer A. R., Maniatis T., Green M. R. Excision of an intact intron as a novel lariat structure during pre-mRNA splicing in vitro. Cell. 1984 Aug;38(1):317–331. doi: 10.1016/0092-8674(84)90553-1. [DOI] [PubMed] [Google Scholar]
  35. Ruskin B., Zamore P. D., Green M. R. A factor, U2AF, is required for U2 snRNP binding and splicing complex assembly. Cell. 1988 Jan 29;52(2):207–219. doi: 10.1016/0092-8674(88)90509-0. [DOI] [PubMed] [Google Scholar]
  36. Schwer B., Guthrie C. PRP16 is an RNA-dependent ATPase that interacts transiently with the spliceosome. Nature. 1991 Feb 7;349(6309):494–499. doi: 10.1038/349494a0. [DOI] [PubMed] [Google Scholar]
  37. Siliciano P. G., Guthrie C. 5' splice site selection in yeast: genetic alterations in base-pairing with U1 reveal additional requirements. Genes Dev. 1988 Oct;2(10):1258–1267. doi: 10.1101/gad.2.10.1258. [DOI] [PubMed] [Google Scholar]
  38. Singh R., Valcárcel J., Green M. R. Distinct binding specificities and functions of higher eukaryotic polypyrimidine tract-binding proteins. Science. 1995 May 26;268(5214):1173–1176. doi: 10.1126/science.7761834. [DOI] [PubMed] [Google Scholar]
  39. Smith C. W., Porro E. B., Patton J. G., Nadal-Ginard B. Scanning from an independently specified branch point defines the 3' splice site of mammalian introns. Nature. 1989 Nov 16;342(6247):243–247. doi: 10.1038/342243a0. [DOI] [PubMed] [Google Scholar]
  40. Sontheimer E. J., Steitz J. A. The U5 and U6 small nuclear RNAs as active site components of the spliceosome. Science. 1993 Dec 24;262(5142):1989–1996. doi: 10.1126/science.8266094. [DOI] [PubMed] [Google Scholar]
  41. Staknis D., Reed R. Direct interactions between pre-mRNA and six U2 small nuclear ribonucleoproteins during spliceosome assembly. Mol Cell Biol. 1994 May;14(5):2994–3005. doi: 10.1128/mcb.14.5.2994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Sun J. S., Manley J. L. A novel U2-U6 snRNA structure is necessary for mammalian mRNA splicing. Genes Dev. 1995 Apr 1;9(7):843–854. doi: 10.1101/gad.9.7.843. [DOI] [PubMed] [Google Scholar]
  43. Swanson M. S., Dreyfuss G. RNA binding specificity of hnRNP proteins: a subset bind to the 3' end of introns. EMBO J. 1988 Nov;7(11):3519–3529. doi: 10.1002/j.1460-2075.1988.tb03228.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Séraphin B., Kretzner L., Rosbash M. A U1 snRNA:pre-mRNA base pairing interaction is required early in yeast spliceosome assembly but does not uniquely define the 5' cleavage site. EMBO J. 1988 Aug;7(8):2533–2538. doi: 10.1002/j.1460-2075.1988.tb03101.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  45. Valcárcel J., Singh R., Zamore P. D., Green M. R. The protein Sex-lethal antagonizes the splicing factor U2AF to regulate alternative splicing of transformer pre-mRNA. Nature. 1993 Mar 11;362(6416):171–175. doi: 10.1038/362171a0. [DOI] [PubMed] [Google Scholar]
  46. Wallace J. C., Edmonds M. Polyadenylylated nuclear RNA contains branches. Proc Natl Acad Sci U S A. 1983 Feb;80(4):950–954. doi: 10.1073/pnas.80.4.950. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Wu J., Manley J. L. Mammalian pre-mRNA branch site selection by U2 snRNP involves base pairing. Genes Dev. 1989 Oct;3(10):1553–1561. doi: 10.1101/gad.3.10.1553. [DOI] [PubMed] [Google Scholar]
  48. Wyatt J. R., Sontheimer E. J., Steitz J. A. Site-specific cross-linking of mammalian U5 snRNP to the 5' splice site before the first step of pre-mRNA splicing. Genes Dev. 1992 Dec;6(12B):2542–2553. doi: 10.1101/gad.6.12b.2542. [DOI] [PubMed] [Google Scholar]
  49. Zahler A. M., Lane W. S., Stolk J. A., Roth M. B. SR proteins: a conserved family of pre-mRNA splicing factors. Genes Dev. 1992 May;6(5):837–847. doi: 10.1101/gad.6.5.837. [DOI] [PubMed] [Google Scholar]
  50. Zamore P. D., Green M. R. Biochemical characterization of U2 snRNP auxiliary factor: an essential pre-mRNA splicing factor with a novel intranuclear distribution. EMBO J. 1991 Jan;10(1):207–214. doi: 10.1002/j.1460-2075.1991.tb07937.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Zamore P. D., Green M. R. Identification, purification, and biochemical characterization of U2 small nuclear ribonucleoprotein auxiliary factor. Proc Natl Acad Sci U S A. 1989 Dec;86(23):9243–9247. doi: 10.1073/pnas.86.23.9243. [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Zamore P. D., Patton J. G., Green M. R. Cloning and domain structure of the mammalian splicing factor U2AF. Nature. 1992 Feb 13;355(6361):609–614. doi: 10.1038/355609a0. [DOI] [PubMed] [Google Scholar]
  53. Zhuang Y., Weiner A. M. A compensatory base change in U1 snRNA suppresses a 5' splice site mutation. Cell. 1986 Sep 12;46(6):827–835. doi: 10.1016/0092-8674(86)90064-4. [DOI] [PubMed] [Google Scholar]
  54. Zhuang Y., Weiner A. M. A compensatory base change in human U2 snRNA can suppress a branch site mutation. Genes Dev. 1989 Oct;3(10):1545–1552. doi: 10.1101/gad.3.10.1545. [DOI] [PubMed] [Google Scholar]
  55. Zillmann M., Zapp M. L., Berget S. M. Gel electrophoretic isolation of splicing complexes containing U1 small nuclear ribonucleoprotein particles. Mol Cell Biol. 1988 Feb;8(2):814–821. doi: 10.1128/mcb.8.2.814. [DOI] [PMC free article] [PubMed] [Google Scholar]

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