Abstract
We describe a heterologous, Semliki Forest virus (SFV)-driven packaging system for the production of infectious recombinant Moloney murine leukemia virus particles. The gag-pol and env genes, as well as a recombinant retrovirus genome (LTR-psi (+)-neoR-LTR), were inserted into individual SFV1 expression plasmids. Replication-competent RNAs were transcribed in vitro and introduced into the cytoplasm of BHK-21 cells using electroporation. The expressed Moloney murine leukemia virus structural proteins produced extracellular virus-like particles. In these particles the gag precursor was processed into mature products, indicating that the particles contained an active protease. The protease of the gag-pol fusion protein was also shown to be active in a trans-complementation assay using a large excess of Pr65gag. Moreover, the particles possessed reverse transcriptase (RT) activity as measured in an in vitro assay. Cotransfection of BHK-21 cells by all three SFV1 constructs resulted in the production of transduction-competent particles at 4 x 10(6) colony-forming units (cfu)/ml during a 5-hr incubation period. Altogether, 2.9 x 10(7) transduction-competent particles were obtained from about 4 x 10(6) transfected cells. Thus, this system represents the first RNA-based packaging system for the production of infectious retroviral particles. The facts that no helper virus could be detected in the virus stocks and that particles carrying the amphotropic envelope could be produced with similar efficiency as those that carry the ecotropic envelope make the system very interesting for gene therapy.
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- Colicelli J., Goff S. P. Sequence and spacing requirements of a retrovirus integration site. J Mol Biol. 1988 Jan 5;199(1):47–59. doi: 10.1016/0022-2836(88)90378-6. [DOI] [PubMed] [Google Scholar]
- Goff S. P. Genetics of retroviral integration. Annu Rev Genet. 1992;26:527–544. doi: 10.1146/annurev.ge.26.120192.002523. [DOI] [PubMed] [Google Scholar]
- Goff S., Traktman P., Baltimore D. Isolation and properties of Moloney murine leukemia virus mutants: use of a rapid assay for release of virion reverse transcriptase. J Virol. 1981 Apr;38(1):239–248. doi: 10.1128/jvi.38.1.239-248.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horton R. M., Hunt H. D., Ho S. N., Pullen J. K., Pease L. R. Engineering hybrid genes without the use of restriction enzymes: gene splicing by overlap extension. Gene. 1989 Apr 15;77(1):61–68. doi: 10.1016/0378-1119(89)90359-4. [DOI] [PubMed] [Google Scholar]
- Jacks T., Power M. D., Masiarz F. R., Luciw P. A., Barr P. J., Varmus H. E. Characterization of ribosomal frameshifting in HIV-1 gag-pol expression. Nature. 1988 Jan 21;331(6153):280–283. doi: 10.1038/331280a0. [DOI] [PubMed] [Google Scholar]
- Jacks T., Varmus H. E. Expression of the Rous sarcoma virus pol gene by ribosomal frameshifting. Science. 1985 Dec 13;230(4731):1237–1242. doi: 10.1126/science.2416054. [DOI] [PubMed] [Google Scholar]
- Katoh I., Yoshinaka Y., Rein A., Shibuya M., Odaka T., Oroszlan S. Murine leukemia virus maturation: protease region required for conversion from "immature" to "mature" core form and for virus infectivity. Virology. 1985 Sep;145(2):280–292. doi: 10.1016/0042-6822(85)90161-8. [DOI] [PubMed] [Google Scholar]
- Katz R. A., Skalka A. M. The retroviral enzymes. Annu Rev Biochem. 1994;63:133–173. doi: 10.1146/annurev.bi.63.070194.001025. [DOI] [PubMed] [Google Scholar]
- Landau N. R., Littman D. R. Packaging system for rapid production of murine leukemia virus vectors with variable tropism. J Virol. 1992 Aug;66(8):5110–5113. doi: 10.1128/jvi.66.8.5110-5113.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Liljeström P., Garoff H. A new generation of animal cell expression vectors based on the Semliki Forest virus replicon. Biotechnology (N Y) 1991 Dec;9(12):1356–1361. doi: 10.1038/nbt1291-1356. [DOI] [PubMed] [Google Scholar]
- Lusa S., Garoff H., Liljeström P. Fate of the 6K membrane protein of Semliki Forest virus during virus assembly. Virology. 1991 Dec;185(2):843–846. doi: 10.1016/0042-6822(91)90556-q. [DOI] [PubMed] [Google Scholar]
- Mann R., Mulligan R. C., Baltimore D. Construction of a retrovirus packaging mutant and its use to produce helper-free defective retrovirus. Cell. 1983 May;33(1):153–159. doi: 10.1016/0092-8674(83)90344-6. [DOI] [PubMed] [Google Scholar]
- Miller A. D., Buttimore C. Redesign of retrovirus packaging cell lines to avoid recombination leading to helper virus production. Mol Cell Biol. 1986 Aug;6(8):2895–2902. doi: 10.1128/mcb.6.8.2895. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miller A. D. Human gene therapy comes of age. Nature. 1992 Jun 11;357(6378):455–460. doi: 10.1038/357455a0. [DOI] [PubMed] [Google Scholar]
- Miller A. D. Retrovirus packaging cells. Hum Gene Ther. 1990 Spring;1(1):5–14. doi: 10.1089/hum.1990.1.1-5. [DOI] [PubMed] [Google Scholar]
- Miller A. D., Rosman G. J. Improved retroviral vectors for gene transfer and expression. Biotechniques. 1989 Oct;7(9):980-2, 984-6, 989-90. [PMC free article] [PubMed] [Google Scholar]
- Morgan R. A., Anderson W. F. Human gene therapy. Annu Rev Biochem. 1993;62:191–217. doi: 10.1146/annurev.bi.62.070193.001203. [DOI] [PubMed] [Google Scholar]
- Pear W. S., Nolan G. P., Scott M. L., Baltimore D. Production of high-titer helper-free retroviruses by transient transfection. Proc Natl Acad Sci U S A. 1993 Sep 15;90(18):8392–8396. doi: 10.1073/pnas.90.18.8392. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ramsey C. A., Panganiban A. T. Replication of the retroviral terminal repeat sequence during in vivo reverse transcription. J Virol. 1993 Jul;67(7):4114–4121. doi: 10.1128/jvi.67.7.4114-4121.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sjöberg E. M., Suomalainen M., Garoff H. A significantly improved Semliki Forest virus expression system based on translation enhancer segments from the viral capsid gene. Biotechnology (N Y) 1994 Nov;12(11):1127–1131. doi: 10.1038/nbt1194-1127. [DOI] [PubMed] [Google Scholar]
- Sonigo P., Barker C., Hunter E., Wain-Hobson S. Nucleotide sequence of Mason-Pfizer monkey virus: an immunosuppressive D-type retrovirus. Cell. 1986 May 9;45(3):375–385. doi: 10.1016/0092-8674(86)90323-5. [DOI] [PubMed] [Google Scholar]
- Strauss J. H., Strauss E. G. The alphaviruses: gene expression, replication, and evolution. Microbiol Rev. 1994 Sep;58(3):491–562. doi: 10.1128/mr.58.3.491-562.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Su T. Z., el-Gewely M. R. A multisite-directed mutagenesis using T7 DNA polymerase: application for reconstructing a mammalian gene. Gene. 1988 Sep 15;69(1):81–89. doi: 10.1016/0378-1119(88)90380-0. [DOI] [PubMed] [Google Scholar]
- Suomalainen M., Garoff H. Incorporation of homologous and heterologous proteins into the envelope of Moloney murine leukemia virus. J Virol. 1994 Aug;68(8):4879–4889. doi: 10.1128/jvi.68.8.4879-4889.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wahlberg J. M., Boere W. A., Garoff H. The heterodimeric association between the membrane proteins of Semliki Forest virus changes its sensitivity to low pH during virus maturation. J Virol. 1989 Dec;63(12):4991–4997. doi: 10.1128/jvi.63.12.4991-4997.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Whitcomb J. M., Hughes S. H. Retroviral reverse transcription and integration: progress and problems. Annu Rev Cell Biol. 1992;8:275–306. doi: 10.1146/annurev.cb.08.110192.001423. [DOI] [PubMed] [Google Scholar]
- Xiong C., Levis R., Shen P., Schlesinger S., Rice C. M., Huang H. V. Sindbis virus: an efficient, broad host range vector for gene expression in animal cells. Science. 1989 Mar 3;243(4895):1188–1191. doi: 10.1126/science.2922607. [DOI] [PubMed] [Google Scholar]
- Yoshinaka Y., Katoh I., Copeland T. D., Oroszlan S. Murine leukemia virus protease is encoded by the gag-pol gene and is synthesized through suppression of an amber termination codon. Proc Natl Acad Sci U S A. 1985 Mar;82(6):1618–1622. doi: 10.1073/pnas.82.6.1618. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van Beusechem V. W., Kukler A., Einerhand M. P., Bakx T. A., van der Eb A. J., van Bekkum D. W., Valerio D. Expression of human adenosine deaminase in mice transplanted with hemopoietic stem cells infected with amphotropic retroviruses. J Exp Med. 1990 Sep 1;172(3):729–736. doi: 10.1084/jem.172.3.729. [DOI] [PMC free article] [PubMed] [Google Scholar]