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. 1994 Jul;14(7):4682–4693. doi: 10.1128/mcb.14.7.4682

Sequence elements upstream of the 3' cleavage site confer substrate strength to the adenovirus L1 and L3 polyadenylation sites.

J Prescott 1, E Falck-Pedersen 1
PMCID: PMC358841  PMID: 7911973

Abstract

The adenovirus major late transcription unit is a well-characterized transcription unit which relies heavily on alternative pre-mRNA processing to generate distinct populations of mRNA during the early and late stages of viral infection. In the early stage of infection, two major late transcription unit mRNA transcripts are generated through use of the first (L1) of five available poly(A) sites (L1 through L5). This contrasts with the late stage of infection when as many as 45 distinct mRNAs are generated, with each of the five poly(A) sites being used. In previous work characterizing elements involved in alternative poly(A) site use, we showed that the L1 poly(A) site is processed less efficiently than the L3 poly(A) site both in vitro and in vivo. Because of the dramatic difference in processing efficiency and the role processing efficiency plays in production of steady-state levels of mRNA, we have identified the sequence elements that account for the differences in L1 and L3 poly(A) site processing efficiency. We have found that the element most likely to be responsible for poly(A) site strength, the GU/U-rich downstream element, plays a minor role in the different processing efficiencies observed for the L1 and L3 poly(A) sites. The sequence element most responsible for inefficient processing of the L1 poly(A) site includes the L1 AAUAAA consensus sequence and those sequences which immediately surround the consensus hexanucleotide. This region of the L1 poly(A) site contributes to an inability to form a stable processing complex with the downstream GU/U-rich element. In contrast to the L1 element, the L3 poly(A) site has a consensus hexanucleotide and surrounding sequences which can form a stable processing complex in cooperation with the downstream GU/U-rich element. The L3 poly(A) site is also aided by the presence of sequences upstream of the hexanucleotide which facilitate processing efficiency. The sequence UUCUUUUU, present in the L3 upstream region, is shown to enhance processing efficiency as well as stable complex formation (shown by increased binding of the 64-kDa cleavage stimulatory factor subunit) and acts as a binding site for heterogeneous nuclear ribonucleoprotein C proteins.

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Selected References

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  1. Bienroth S., Wahle E., Suter-Crazzolara C., Keller W. Purification of the cleavage and polyadenylation factor involved in the 3'-processing of messenger RNA precursors. J Biol Chem. 1991 Oct 15;266(29):19768–19776. [PubMed] [Google Scholar]
  2. Birnstiel M. L., Busslinger M., Strub K. Transcription termination and 3' processing: the end is in site! Cell. 1985 Jun;41(2):349–359. doi: 10.1016/s0092-8674(85)80007-6. [DOI] [PubMed] [Google Scholar]
  3. Brasier A. R., Tate J. E., Habener J. F. Optimized use of the firefly luciferase assay as a reporter gene in mammalian cell lines. Biotechniques. 1989 Nov-Dec;7(10):1116–1122. [PubMed] [Google Scholar]
  4. Carswell S., Alwine J. C. Efficiency of utilization of the simian virus 40 late polyadenylation site: effects of upstream sequences. Mol Cell Biol. 1989 Oct;9(10):4248–4258. doi: 10.1128/mcb.9.10.4248. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Cherrington J., Ganem D. Regulation of polyadenylation in human immunodeficiency virus (HIV): contributions of promoter proximity and upstream sequences. EMBO J. 1992 Apr;11(4):1513–1524. doi: 10.1002/j.1460-2075.1992.tb05196.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Cherrington J., Russnak R., Ganem D. Upstream sequences and cap proximity in the regulation of polyadenylation in ground squirrel hepatitis virus. J Virol. 1992 Dec;66(12):7589–7596. doi: 10.1128/jvi.66.12.7589-7596.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Choi Y. D., Dreyfuss G. Monoclonal antibody characterization of the C proteins of heterogeneous nuclear ribonucleoprotein complexes in vertebrate cells. J Cell Biol. 1984 Dec;99(6):1997–1204. doi: 10.1083/jcb.99.6.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
  9. Christofori G., Keller W. 3' cleavage and polyadenylation of mRNA precursors in vitro requires a poly(A) polymerase, a cleavage factor, and a snRNP. Cell. 1988 Sep 9;54(6):875–889. doi: 10.1016/s0092-8674(88)91263-9. [DOI] [PubMed] [Google Scholar]
  10. Christofori G., Keller W. Poly(A) polymerase purified from HeLa cell nuclear extract is required for both cleavage and polyadenylation of pre-mRNA in vitro. Mol Cell Biol. 1989 Jan;9(1):193–203. doi: 10.1128/mcb.9.1.193. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Citron B., Falck-Pedersen E., Salditt-Georgieff M., Darnell J. E., Jr Transcription termination occurs within a 1000 base pair region downstream from the poly(A) site of the mouse beta-globin (major) gene. Nucleic Acids Res. 1984 Nov 26;12(22):8723–8731. doi: 10.1093/nar/12.22.8723. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Darnell J. E., Jr Variety in the level of gene control in eukaryotic cells. Nature. 1982 Jun 3;297(5865):365–371. doi: 10.1038/297365a0. [DOI] [PubMed] [Google Scholar]
  13. DeZazzo J. D., Falck-Pedersen E., Imperiale M. J. Sequences regulating temporal poly(A) site switching in the adenovirus major late transcription unit. Mol Cell Biol. 1991 Dec;11(12):5977–5984. doi: 10.1128/mcb.11.12.5977. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. DeZazzo J. D., Imperiale M. J. Sequences upstream of AAUAAA influence poly(A) site selection in a complex transcription unit. Mol Cell Biol. 1989 Nov;9(11):4951–4961. doi: 10.1128/mcb.9.11.4951. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. DeZazzo J. D., Kilpatrick J. E., Imperiale M. J. Involvement of long terminal repeat U3 sequences overlapping the transcription control region in human immunodeficiency virus type 1 mRNA 3' end formation. Mol Cell Biol. 1991 Mar;11(3):1624–1630. doi: 10.1128/mcb.11.3.1624. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Edwalds-Gilbert G., Prescott J., Falck-Pedersen E. 3' RNA processing efficiency plays a primary role in generating termination-competent RNA polymerase II elongation complexes. Mol Cell Biol. 1993 Jun;13(6):3472–3480. doi: 10.1128/mcb.13.6.3472. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Falck-Pedersen E., Logan J. Regulation of poly(A) site selection in adenovirus. J Virol. 1989 Feb;63(2):532–541. doi: 10.1128/jvi.63.2.532-541.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Feinberg A. P., Vogelstein B. A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem. 1983 Jul 1;132(1):6–13. doi: 10.1016/0003-2697(83)90418-9. [DOI] [PubMed] [Google Scholar]
  19. Fitzgerald M., Shenk T. The sequence 5'-AAUAAA-3'forms parts of the recognition site for polyadenylation of late SV40 mRNAs. Cell. 1981 Apr;24(1):251–260. doi: 10.1016/0092-8674(81)90521-3. [DOI] [PubMed] [Google Scholar]
  20. Gil A., Proudfoot N. J. A sequence downstream of AAUAAA is required for rabbit beta-globin mRNA 3'-end formation. 1984 Nov 29-Dec 5Nature. 312(5993):473–474. doi: 10.1038/312473a0. [DOI] [PubMed] [Google Scholar]
  21. Gilmartin G. M., McDevitt M. A., Nevins J. R. Multiple factors are required for specific RNA cleavage at a poly(A) addition site. Genes Dev. 1988 May;2(5):578–587. doi: 10.1101/gad.2.5.578. [DOI] [PubMed] [Google Scholar]
  22. Gilmartin G. M., Nevins J. R. An ordered pathway of assembly of components required for polyadenylation site recognition and processing. Genes Dev. 1989 Dec;3(12B):2180–2190. doi: 10.1101/gad.3.12b.2180. [DOI] [PubMed] [Google Scholar]
  23. Gilmartin G. M., Nevins J. R. Molecular analyses of two poly(A) site-processing factors that determine the recognition and efficiency of cleavage of the pre-mRNA. Mol Cell Biol. 1991 May;11(5):2432–2438. doi: 10.1128/mcb.11.5.2432. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Green T. L., Hart R. P. Mutations in poly(A) site downstream elements affect in vitro cleavage activity. Mol Cell Biol. 1988 Apr;8(4):1839–1841. doi: 10.1128/mcb.8.4.1839. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Hales K. H., Birk J. M., Imperiale M. J. Analysis of adenovirus type 2 L1 RNA 3'-end formation in vivo and in vitro. J Virol. 1988 Apr;62(4):1464–1468. doi: 10.1128/jvi.62.4.1464-1468.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Hart R. P., McDevitt M. A., Ali H., Nevins J. R. Definition of essential sequences and functional equivalence of elements downstream of the adenovirus E2A and the early simian virus 40 polyadenylation sites. Mol Cell Biol. 1985 Nov;5(11):2975–2983. doi: 10.1128/mcb.5.11.2975. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Hart R. P., McDevitt M. A., Nevins J. R. Poly(A) site cleavage in a HeLa nuclear extract is dependent on downstream sequences. Cell. 1985 Dec;43(3 Pt 2):677–683. doi: 10.1016/0092-8674(85)90240-5. [DOI] [PubMed] [Google Scholar]
  28. Huang M. T., Gorman C. M. Intervening sequences increase efficiency of RNA 3' processing and accumulation of cytoplasmic RNA. Nucleic Acids Res. 1990 Feb 25;18(4):937–947. doi: 10.1093/nar/18.4.937. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Keller W., Bienroth S., Lang K. M., Christofori G. Cleavage and polyadenylation factor CPF specifically interacts with the pre-mRNA 3' processing signal AAUAAA. EMBO J. 1991 Dec;10(13):4241–4249. doi: 10.1002/j.1460-2075.1991.tb05002.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Leff S. E., Rosenfeld M. G., Evans R. M. Complex transcriptional units: diversity in gene expression by alternative RNA processing. Annu Rev Biochem. 1986;55:1091–1117. doi: 10.1146/annurev.bi.55.070186.005303. [DOI] [PubMed] [Google Scholar]
  31. Levitt N., Briggs D., Gil A., Proudfoot N. J. Definition of an efficient synthetic poly(A) site. Genes Dev. 1989 Jul;3(7):1019–1025. doi: 10.1101/gad.3.7.1019. [DOI] [PubMed] [Google Scholar]
  32. Manley J. L. Accurate and specific polyadenylation of mRNA precursors in a soluble whole-cell lysate. Cell. 1983 Jun;33(2):595–605. doi: 10.1016/0092-8674(83)90440-3. [DOI] [PubMed] [Google Scholar]
  33. Manley J. L. Polyadenylation of mRNA precursors. Biochim Biophys Acta. 1988 May 6;950(1):1–12. doi: 10.1016/0167-4781(88)90067-x. [DOI] [PubMed] [Google Scholar]
  34. McDevitt M. A., Gilmartin G. M., Reeves W. H., Nevins J. R. Multiple factors are required for poly(A) addition to a mRNA 3' end. Genes Dev. 1988 May;2(5):588–597. doi: 10.1101/gad.2.5.588. [DOI] [PubMed] [Google Scholar]
  35. McDevitt M. A., Hart R. P., Wong W. W., Nevins J. R. Sequences capable of restoring poly(A) site function define two distinct downstream elements. EMBO J. 1986 Nov;5(11):2907–2913. doi: 10.1002/j.1460-2075.1986.tb04586.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. McDevitt M. A., Imperiale M. J., Ali H., Nevins J. R. Requirement of a downstream sequence for generation of a poly(A) addition site. Cell. 1984 Jul;37(3):993–999. doi: 10.1016/0092-8674(84)90433-1. [DOI] [PubMed] [Google Scholar]
  37. McLauchlan J., Gaffney D., Whitton J. L., Clements J. B. The consensus sequence YGTGTTYY located downstream from the AATAAA signal is required for efficient formation of mRNA 3' termini. Nucleic Acids Res. 1985 Feb 25;13(4):1347–1368. doi: 10.1093/nar/13.4.1347. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Montell C., Fisher E. F., Caruthers M. H., Berk A. J. Inhibition of RNA cleavage but not polyadenylation by a point mutation in mRNA 3' consensus sequence AAUAAA. Nature. 1983 Oct 13;305(5935):600–605. doi: 10.1038/305600a0. [DOI] [PubMed] [Google Scholar]
  39. Moore C. L., Chen J., Whoriskey J. Two proteins crosslinked to RNA containing the adenovirus L3 poly(A) site require the AAUAAA sequence for binding. EMBO J. 1988 Oct;7(10):3159–3169. doi: 10.1002/j.1460-2075.1988.tb03183.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Moore C. L., Sharp P. A. Accurate cleavage and polyadenylation of exogenous RNA substrate. Cell. 1985 Jul;41(3):845–855. doi: 10.1016/s0092-8674(85)80065-9. [DOI] [PubMed] [Google Scholar]
  41. Moore C. L., Sharp P. A. Site-specific polyadenylation in a cell-free reaction. Cell. 1984 Mar;36(3):581–591. doi: 10.1016/0092-8674(84)90337-4. [DOI] [PubMed] [Google Scholar]
  42. Moore C. L., Skolnik-David H., Sharp P. A. Analysis of RNA cleavage at the adenovirus-2 L3 polyadenylation site. EMBO J. 1986 Aug;5(8):1929–1938. doi: 10.1002/j.1460-2075.1986.tb04446.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  43. Nevins J. R., Chen-Kiang S. Processing of adenovirus nuclear RNA to mRNA. Adv Virus Res. 1981;26:1–35. doi: 10.1016/s0065-3527(08)60419-4. [DOI] [PubMed] [Google Scholar]
  44. Niwa M., MacDonald C. C., Berget S. M. Are vertebrate exons scanned during splice-site selection? Nature. 1992 Nov 19;360(6401):277–280. doi: 10.1038/360277a0. [DOI] [PubMed] [Google Scholar]
  45. Peterson M. L., Perry R. P. The regulated production of mu m and mu s mRNA is dependent on the relative efficiencies of mu s poly(A) site usage and the c mu 4-to-M1 splice. Mol Cell Biol. 1989 Feb;9(2):726–738. doi: 10.1128/mcb.9.2.726. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Prescott J. C., Falck-Pedersen E. Varied poly(A) site efficiency in the adenovirus major late transcription unit. J Biol Chem. 1992 Apr 25;267(12):8175–8181. [PubMed] [Google Scholar]
  47. Russnak R. H. Regulation of polyadenylation in hepatitis B viruses: stimulation by the upstream activating signal PS1 is orientation-dependent, distance-independent, and additive. Nucleic Acids Res. 1991 Dec 11;19(23):6449–6456. doi: 10.1093/nar/19.23.6449. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Russnak R., Ganem D. Sequences 5' to the polyadenylation signal mediate differential poly(A) site use in hepatitis B viruses. Genes Dev. 1990 May;4(5):764–776. doi: 10.1101/gad.4.5.764. [DOI] [PubMed] [Google Scholar]
  49. Ryner L. C., Takagaki Y., Manley J. L. Sequences downstream of AAUAAA signals affect pre-mRNA cleavage and polyadenylation in vitro both directly and indirectly. Mol Cell Biol. 1989 Apr;9(4):1759–1771. doi: 10.1128/mcb.9.4.1759. [DOI] [PMC free article] [PubMed] [Google Scholar]
  50. Sadofsky M., Alwine J. C. Sequences on the 3' side of hexanucleotide AAUAAA affect efficiency of cleavage at the polyadenylation site. Mol Cell Biol. 1984 Aug;4(8):1460–1468. doi: 10.1128/mcb.4.8.1460. [DOI] [PMC free article] [PubMed] [Google Scholar]
  51. Sadofsky M., Connelly S., Manley J. L., Alwine J. C. Identification of a sequence element on the 3' side of AAUAAA which is necessary for simian virus 40 late mRNA 3'-end processing. Mol Cell Biol. 1985 Oct;5(10):2713–2719. doi: 10.1128/mcb.5.10.2713. [DOI] [PMC free article] [PubMed] [Google Scholar]
  52. Schek N., Cooke C., Alwine J. C. Definition of the upstream efficiency element of the simian virus 40 late polyadenylation signal by using in vitro analyses. Mol Cell Biol. 1992 Dec;12(12):5386–5393. doi: 10.1128/mcb.12.12.5386. [DOI] [PMC free article] [PubMed] [Google Scholar]
  53. Sheets M. D., Ogg S. C., Wickens M. P. Point mutations in AAUAAA and the poly (A) addition site: effects on the accuracy and efficiency of cleavage and polyadenylation in vitro. Nucleic Acids Res. 1990 Oct 11;18(19):5799–5805. doi: 10.1093/nar/18.19.5799. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Swanson M. S., Dreyfuss G. Classification and purification of proteins of heterogeneous nuclear ribonucleoprotein particles by RNA-binding specificities. Mol Cell Biol. 1988 May;8(5):2237–2241. doi: 10.1128/mcb.8.5.2237. [DOI] [PMC free article] [PubMed] [Google Scholar]
  55. Takagaki Y., MacDonald C. C., Shenk T., Manley J. L. The human 64-kDa polyadenylylation factor contains a ribonucleoprotein-type RNA binding domain and unusual auxiliary motifs. Proc Natl Acad Sci U S A. 1992 Feb 15;89(4):1403–1407. doi: 10.1073/pnas.89.4.1403. [DOI] [PMC free article] [PubMed] [Google Scholar]
  56. Takagaki Y., Manley J. L., MacDonald C. C., Wilusz J., Shenk T. A multisubunit factor, CstF, is required for polyadenylation of mammalian pre-mRNAs. Genes Dev. 1990 Dec;4(12A):2112–2120. doi: 10.1101/gad.4.12a.2112. [DOI] [PubMed] [Google Scholar]
  57. Takagaki Y., Ryner L. C., Manley J. L. Four factors are required for 3'-end cleavage of pre-mRNAs. Genes Dev. 1989 Nov;3(11):1711–1724. doi: 10.1101/gad.3.11.1711. [DOI] [PubMed] [Google Scholar]
  58. Takagaki Y., Ryner L. C., Manley J. L. Separation and characterization of a poly(A) polymerase and a cleavage/specificity factor required for pre-mRNA polyadenylation. Cell. 1988 Mar 11;52(5):731–742. doi: 10.1016/0092-8674(88)90411-4. [DOI] [PubMed] [Google Scholar]
  59. Valsamakis A., Zeichner S., Carswell S., Alwine J. C. The human immunodeficiency virus type 1 polyadenylylation signal: a 3' long terminal repeat element upstream of the AAUAAA necessary for efficient polyadenylylation. Proc Natl Acad Sci U S A. 1991 Mar 15;88(6):2108–2112. doi: 10.1073/pnas.88.6.2108. [DOI] [PMC free article] [PubMed] [Google Scholar]
  60. Wahle E., Keller W. The biochemistry of 3'-end cleavage and polyadenylation of messenger RNA precursors. Annu Rev Biochem. 1992;61:419–440. doi: 10.1146/annurev.bi.61.070192.002223. [DOI] [PubMed] [Google Scholar]
  61. Weiss E. A., Gilmartin G. M., Nevins J. R. Poly(A) site efficiency reflects the stability of complex formation involving the downstream element. EMBO J. 1991 Jan;10(1):215–219. doi: 10.1002/j.1460-2075.1991.tb07938.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  62. Wickens M. How the messenger got its tail: addition of poly(A) in the nucleus. Trends Biochem Sci. 1990 Jul;15(7):277–281. doi: 10.1016/0968-0004(90)90054-f. [DOI] [PubMed] [Google Scholar]
  63. Wickens M., Stephenson P. Role of the conserved AAUAAA sequence: four AAUAAA point mutants prevent messenger RNA 3' end formation. Science. 1984 Nov 30;226(4678):1045–1051. doi: 10.1126/science.6208611. [DOI] [PubMed] [Google Scholar]
  64. Wigley P. L., Sheets M. D., Zarkower D. A., Whitmer M. E., Wickens M. Polyadenylation of mRNA: minimal substrates and a requirement for the 2' hydroxyl of the U in AAUAAA. Mol Cell Biol. 1990 Apr;10(4):1705–1713. doi: 10.1128/mcb.10.4.1705. [DOI] [PMC free article] [PubMed] [Google Scholar]
  65. Wilson-Gunn S. I., Kilpatrick J. E., Imperiale M. J. Regulated adenovirus mRNA 3'-end formation in a coupled in vitro transcription-processing system. J Virol. 1992 Sep;66(9):5418–5424. doi: 10.1128/jvi.66.9.5418-5424.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  66. Wilusz J., Feig D. I., Shenk T. The C proteins of heterogeneous nuclear ribonucleoprotein complexes interact with RNA sequences downstream of polyadenylation cleavage sites. Mol Cell Biol. 1988 Oct;8(10):4477–4483. doi: 10.1128/mcb.8.10.4477. [DOI] [PMC free article] [PubMed] [Google Scholar]
  67. Wilusz J., Shenk T. A uridylate tract mediates efficient heterogeneous nuclear ribonucleoprotein C protein-RNA cross-linking and functionally substitutes for the downstream element of the polyadenylation signal. Mol Cell Biol. 1990 Dec;10(12):6397–6407. doi: 10.1128/mcb.10.12.6397. [DOI] [PMC free article] [PubMed] [Google Scholar]
  68. Wilusz J., Shenk T., Takagaki Y., Manley J. L. A multicomponent complex is required for the AAUAAA-dependent cross-linking of a 64-kilodalton protein to polyadenylation substrates. Mol Cell Biol. 1990 Mar;10(3):1244–1248. doi: 10.1128/mcb.10.3.1244. [DOI] [PMC free article] [PubMed] [Google Scholar]
  69. Woychik R. P., Lyons R. H., Post L., Rottman F. M. Requirement for the 3' flanking region of the bovine growth hormone gene for accurate polyadenylylation. Proc Natl Acad Sci U S A. 1984 Jul;81(13):3944–3948. doi: 10.1073/pnas.81.13.3944. [DOI] [PMC free article] [PubMed] [Google Scholar]
  70. Zawel L., Reinberg D. Initiation of transcription by RNA polymerase II: a multi-step process. Prog Nucleic Acid Res Mol Biol. 1993;44:67–108. doi: 10.1016/s0079-6603(08)60217-2. [DOI] [PubMed] [Google Scholar]

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