title: A preliminary step of a novel strategy in suicide gene therapy with lentiviral vector.
abstract: BACKGROUND
  One of the challenges in lentiviral vector-based suicide gene therapy by toxin or apoptosis-inducing genes is death of packaging cells. Therefore, the process of production of these lentiviral particles would be stopped in this step. We proposed that insertion of a reverse promoter between R and U5 regions of 5' long terminal repeat (LTR) in transfer plasmid could be considered as a solution for this problem. But it is not known, whether the insertion of RΔU3 sequence between the promoter and target gene in proviral genome during the life-cycle of lentivirus may interfere whit gene expression in target cells.
  
  
  METHODS
  THE FOLLOWING WERE PERFORMED IN THIS STUDY: insertion of RΔU3 sequence in pEGFP-N1 plasmid, evaluation of the expression of eGFP gene after calcium phosphate co-precipitation transfection of pCMV-RΔU3-GFP construction in 293T cells, and quantitative assay of eGFP gene by flow cytometry technique.
  
  
  RESULTS
  Our results from flow cytometry technique analysis showed that there was no significant difference between the expression of eGFP gene in transfected cells with pEGFP-N1 and pCMV-RΔU3-GFP plasmids (P > 0.05).
  
  
  CONCLUSIONS
  In this step of our strategy, we demonstrated that modification of orientation and location of promoter may overcome some issues in lentiviral suicide gene therapy, especially when toxin or apoptosis-inducing genes are used.
authors.affiliation: Department of Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Jahan Afrooz
authors.initials: JA
authors.lastname: Ghanbari
authors.affiliation: Department of Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mansoor
authors.initials: M
authors.lastname: Salehi
authors.affiliation: Department of Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Arezoo Karam
authors.initials: AK
authors.lastname: Zadeh
authors.affiliation: Department of Microbiology, Arak University of Medical Sciences, Arak, Iran.
authors.forename: Sedigheh Momen
authors.initials: SM
authors.lastname: Zadeh
authors.affiliation: Physiology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Vahid Bahram
authors.initials: VB
authors.lastname: Beigi
authors.affiliation: Department of Molecular Biology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hossein Khan
authors.initials: HK
authors.lastname: Ahmad
authors.affiliation: Department of Biostatistics of Public Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Behzad
authors.initials: B
authors.lastname: Mahaki
authors.affiliation: MS in Botanical Biology, Department of Biology, Payamnoor University, Isfahan, Iran.
authors.forename: Mina
authors.initials: M
authors.lastname: Beiraghdar
keywords: Apoptosis-inducing genes; CMV promoter; GFP; RΔU3 sequence; gene therapy; lentiviral vectors