Abstract
Using the Escherichia coli lacZ gene product beta-galactosidase as an indicator of gene expression, we analyzed sequences that are required for expression of the Rous sarcoma virus (RSV) genome in avian cells. The RSV long terminal repeat (LTR) and leader region were sufficient to direct the synthesis of high levels of enzymatically active gag-lacZ fusion proteins. A portion of U3 greater than 140 nucleotides upstream from the cap site was essential for gene expression. This element functioned in either orientation, but its activity was attenuated when it was relocated further away from the cap site. The insertion of exogenous LTRs 3' of lacZ augmented the expression of that gene by increasing the level of stable gag-lacZ transcripts. Furthermore, 3' LTRs could partially compensate for certain defects within the 5' LTR. Insertion of various fragmentary LTRs allowed the identification of at least three synergistically acting domains within the 3' LTR that influence gene expression. Interestingly, the gag-lacZ expression was only stimulated by a 3' LTR when the exogenous 3'-untranslated region was adjacent. Our results imply that the two LTRs of a provirus interact in a complex manner to promote high levels of stable transcripts. It was also found that gag-lacZ expression was independent of viral gene products, suggesting that trans-activation is not a key mechanism regulating RSV expression in avian cells.
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Selected References
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- Bizub D., Katz R. A., Skalka A. M. Nucleotide sequence of noncoding regions in Rous-associated virus-2: comparisons delineate conserved regions important in replication and oncogenesis. J Virol. 1984 Feb;49(2):557–565. doi: 10.1128/jvi.49.2.557-565.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Broome S., Gilbert W. Rous sarcoma virus encodes a transcriptional activator. Cell. 1985 Mar;40(3):537–546. doi: 10.1016/0092-8674(85)90202-8. [DOI] [PubMed] [Google Scholar]
- Cullen B. R., Katz R. A., Ju G. Expression of transfected DNA in avian cells can be enhanced in trans by retroviral infection. Mol Cell Biol. 1985 Jul;5(7):1804–1807. doi: 10.1128/mcb.5.7.1804. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cullen B. R., Raymond K., Ju G. Functional analysis of the transcription control region located within the avian retroviral long terminal repeat. Mol Cell Biol. 1985 Mar;5(3):438–447. doi: 10.1128/mcb.5.3.438. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cullen B. R., Raymond K., Ju G. Transcriptional activity of avian retroviral long terminal repeats directly correlates with enhancer activity. J Virol. 1985 Feb;53(2):515–521. doi: 10.1128/jvi.53.2.515-521.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cullen B. R., Skalka A. M., Ju G. Endogenous avian retroviruses contain deficient promoter and leader sequences. Proc Natl Acad Sci U S A. 1983 May;80(10):2946–2950. doi: 10.1073/pnas.80.10.2946. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dorner A. J., Stoye J. P., Coffin J. M. Molecular basis of host range variation in avian retroviruses. J Virol. 1985 Jan;53(1):32–39. doi: 10.1128/jvi.53.1.32-39.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gilmartin G. M., Parsons J. T. Identification of transcriptional elements within the long terminal repeat of Rous sarcoma virus. Mol Cell Biol. 1983 Oct;3(10):1834–1845. doi: 10.1128/mcb.3.10.1834. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hearing P., Shenk T. The adenovirus type 5 E1A transcriptional control region contains a duplicated enhancer element. Cell. 1983 Jul;33(3):695–703. doi: 10.1016/0092-8674(83)90012-0. [DOI] [PubMed] [Google Scholar]
- Herman S. A., Coffin J. M. Differential transcription from the long terminal repeats of integrated avian leukosis virus DNA. J Virol. 1986 Nov;60(2):497–505. doi: 10.1128/jvi.60.2.497-505.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Katz R. A., Omer C. A., Weis J. H., Mitsialis S. A., Faras A. J., Guntaka R. V. Restriction endonuclease and nucleotide sequence analyses of molecularly cloned unintegrated avian tumor virus DNA: structure of large terminal repeats in circle junctions. J Virol. 1982 Apr;42(1):346–351. doi: 10.1128/jvi.42.1.346-351.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Khoury G., Gruss P. Enhancer elements. Cell. 1983 Jun;33(2):313–314. doi: 10.1016/0092-8674(83)90410-5. [DOI] [PubMed] [Google Scholar]
- Laimins L. A., Tsichlis P., Khoury G. Multiple enhancer domains in the 3' terminus of the Prague strain of Rous sarcoma virus. Nucleic Acids Res. 1984 Aug 24;12(16):6427–6442. doi: 10.1093/nar/12.16.6427. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Luciw P. A., Bishop J. M., Varmus H. E., Capecchi M. R. Location and function of retroviral and SV40 sequences that enhance biochemical transformation after microinjection of DNA. Cell. 1983 Jul;33(3):705–716. doi: 10.1016/0092-8674(83)90013-2. [DOI] [PubMed] [Google Scholar]
- Maxam A. M., Gilbert W. Sequencing end-labeled DNA with base-specific chemical cleavages. Methods Enzymol. 1980;65(1):499–560. doi: 10.1016/s0076-6879(80)65059-9. [DOI] [PubMed] [Google Scholar]
- McKnight S., Tjian R. Transcriptional selectivity of viral genes in mammalian cells. Cell. 1986 Sep 12;46(6):795–805. doi: 10.1016/0092-8674(86)90061-9. [DOI] [PubMed] [Google Scholar]
- Melton D. A., Krieg P. A., Rebagliati M. R., Maniatis T., Zinn K., Green M. R. Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter. Nucleic Acids Res. 1984 Sep 25;12(18):7035–7056. doi: 10.1093/nar/12.18.7035. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mermer B., Malamy M., Coffin J. M. Rous sarcoma virus contains sequences which permit expression of the gag gene in Escherichia coli. Mol Cell Biol. 1983 Oct;3(10):1746–1758. doi: 10.1128/mcb.3.10.1746. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mitsialis S. A., Caplan S., Guntaka R. V. An upstream regulatory domain of avian tumor virus long terminal repeat is required for the expression of a procaryotic neomycin gene in eucaryotic cells. Mol Cell Biol. 1983 Nov;3(11):1975–1984. doi: 10.1128/mcb.3.11.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nordheim A., Rich A. Negatively supercoiled simian virus 40 DNA contains Z-DNA segments within transcriptional enhancer sequences. Nature. 1983 Jun 23;303(5919):674–679. doi: 10.1038/303674a0. [DOI] [PubMed] [Google Scholar]
- Norton P. A., Coffin J. M. Bacterial beta-galactosidase as a marker of Rous sarcoma virus gene expression and replication. Mol Cell Biol. 1985 Feb;5(2):281–290. doi: 10.1128/mcb.5.2.281. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Robinson H. L., Blais B. M., Tsichlis P. N., Coffin J. M. At least two regions of the viral genome determine the oncogenic potential of avian leukosis viruses. Proc Natl Acad Sci U S A. 1982 Feb;79(4):1225–1229. doi: 10.1073/pnas.79.4.1225. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schwartz D. E., Tizard R., Gilbert W. Nucleotide sequence of Rous sarcoma virus. Cell. 1983 Mar;32(3):853–869. doi: 10.1016/0092-8674(83)90071-5. [DOI] [PubMed] [Google Scholar]
- Sealy L., Privalsky M. L., Moscovici G., Moscovici C., Bishop J. M. Site-specific mutagenesis of avian erythroblastosis virus: erb-B is required for oncogenicity. Virology. 1983 Oct 15;130(1):155–178. doi: 10.1016/0042-6822(83)90125-3. [DOI] [PubMed] [Google Scholar]
- Sodroski J. G., Goh W. C., Rosen C. A., Salahuddin S. Z., Aldovini A., Franchini G., Wong-Staal F., Gallo R. C., Sugamura K., Hinuma Y. trans-Activation of the human T-cell leukemia virus long terminal repeat correlates with expression of the x-lor protein. J Virol. 1985 Sep;55(3):831–835. doi: 10.1128/jvi.55.3.831-835.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sodroski J. G., Rosen C. A., Haseltine W. A. Trans-acting transcriptional activation of the long terminal repeat of human T lymphotropic viruses in infected cells. Science. 1984 Jul 27;225(4660):381–385. doi: 10.1126/science.6330891. [DOI] [PubMed] [Google Scholar]
- Sorge J., Ricci W., Hughes S. H. cis-Acting RNA packaging locus in the 115-nucleotide direct repeat of Rous sarcoma virus. J Virol. 1983 Dec;48(3):667–675. doi: 10.1128/jvi.48.3.667-675.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsichlis P. N., Coffin J. M. Recombinants between endogenous and exogenous avian tumor viruses: role of the C region and other portions of the genome in the control of replication and transformation. J Virol. 1980 Jan;33(1):238–249. doi: 10.1128/jvi.33.1.238-249.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsichlis P. N., Donehower L., Hager G., Zeller N., Malavarca R., Astrin S., Skalka A. M. Sequence comparison in the crossover region of an oncogenic avian retrovirus recombinant and its nononcogenic parent: genetic regions that control growth rate and oncogenic potential. Mol Cell Biol. 1982 Nov;2(11):1331–1338. doi: 10.1128/mcb.2.11.1331. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang A. H., Quigley G. J., Kolpak F. J., Crawford J. L., van Boom J. H., van der Marel G., Rich A. Molecular structure of a left-handed double helical DNA fragment at atomic resolution. Nature. 1979 Dec 13;282(5740):680–686. doi: 10.1038/282680a0. [DOI] [PubMed] [Google Scholar]
- Wasylyk B., Wasylyk C., Chambon P. Short and long range activation by the SV40 enhancer. Nucleic Acids Res. 1984 Jul 25;12(14):5589–5608. doi: 10.1093/nar/12.14.5589. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weber F., Schaffner W. Enhancer activity correlates with the oncogenic potential of avian retroviruses. EMBO J. 1985 Apr;4(4):949–956. doi: 10.1002/j.1460-2075.1985.tb03723.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weiher H., König M., Gruss P. Multiple point mutations affecting the simian virus 40 enhancer. Science. 1983 Feb 11;219(4585):626–631. doi: 10.1126/science.6297005. [DOI] [PubMed] [Google Scholar]