This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hlavaty, J. Articles by Renner, M. Search for Related Content PubMed PubMed Citation Articles by Hlavaty, J. Articles by Renner, M.

 Previous Article  |  Next Article 

Journal of Virology, February 2004, p. 1384-1392, Vol. 78, No. 3
0022-538X/04/$08.00+0     DOI: 10.1128/JVI.78.3.1384-1392.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Multiple Modifications Allow High-Titer Production of Retroviral Vectors Carrying Heterologous Regulatory Elements

Juraj Hlavaty,^1,2 Anika Stracke,¹ Dieter Klein,¹ Brian Salmons,³ Walter H. Günzburg,^1* and Matthias Renner³

Institute of Virology, University of Veterinary Medicine,¹ Austrianova, A-1210 Vienna, Austria,³ Cancer Research Institute, Slovak Academy of Sciences, Bratislava, Slovak Republic²

Received 17 June 2003/ Accepted 16 October 2003

Tumor-specific expression of therapeutic genes is a prerequisite in many approaches to retrovirus-mediated cancer gene therapy. However, tissue specificity is often associated with a reduction in viral titer. To overcome this problem, we constructed a series of murine leukemia virus (MLV)-based retroviral promoter conversion (ProCon) vectors carrying either the simian virus 40 poly(A) signal trimer (3pA) inserted in the 3' long terminal repeat (LTR) of these vectors or the human cytomegalovirus enhancer region (CMVe) inserted 5' and 3' of the retroviral LTRs. Furthermore, an extended AT stretch/attachment site (AT/att) of wild-type MLV was introduced into the vector. In the vector-producing cells, insertion of the CMVe and/or the 3pA resulted in a three- to fourfold-enhanced marker gene expression compared to the parental vector, whereas insertion of the AT/att gave a slight decrease in expression. The combination of all three modifications had no additional effects. In contrast, however, neomycin selection of infected cells revealed only a slight increase in virus titer with vectors carrying the 3pA modification; the titer was increased by 1 with vectors containing the extended AT/att, although the viral DNA copy numbers in infected cells were similar with both types of vectors. Thus, insufficient integration rather than insufficient reverse transcription and/or production of virus RNA is the major cause for the low titer obtained with the ProCon vectors. The combination of all three modifications resulted in a 2- to 3-log increase in the virus titer. These modifications result in expression targeted ProCon vectors with titers similar to those of nonmodified MLV-based vectors.

---

* Corresponding author. Mailing address: Research Institute for Virology and Biomedicine, University of Veterinary Medicine, Veterinaerplatz 1, A-1210 Vienna, Austria. Phone: 43-1-25077-2301. Fax: 43-1-25077-2390. E-mail: walter.guenzburg{at}vu-wien.ac.at.

---

Journal of Virology, February 2004, p. 1384-1392, Vol. 78, No. 3
0022-538X/04/$08.00+0     DOI: 10.1128/JVI.78.3.1384-1392.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Metzner, C., Mostegl, M. M., Gunzburg, W. H., Salmons, B., Dangerfield, J. A. (2008). Association of glycosylphosphatidylinositol-anchored protein with retroviral particles. FASEB J. 22: 2734-2739 [Abstract] [Full Text]