title: Increase in infectivity of targeted Moloney murine leukemia virus-based gene-delivery vectors through lowering the threshold for fusion.
abstract: Many research groups have developed targeted vectors for gene therapy based on Moloney murine leukemia virus (MoMLV). Despite proper binding of the targeted vector to the target molecule, little or no infectivity of human cells expressing the target molecule has been achieved in most studies. One of the reasons for this lack of infectivity may be steric hindrance within the targeted envelope glycoprotein (Env), impeding the conformational changes required for fusion and infection. Here, attempts were made to solve this problem by mutating key residues within Env of two targeted MoMLV-based vectors, MoMLV-E-Sel and MoMLV-FBP. Selection of key residues was based on an Env with reduced threshold for fusion, that of the CD4-independent human immunodeficiency virus type 2 isolate ROD/B. It was shown here that vectors bearing MoMLV-FBP Env with a V512M substitution had higher titres and faster kinetics of entry than vectors bearing parental targeted Env proteins. This could be due to the partial release of steric constraints that result in an Env with a reduced threshold for fusion.
authors.affiliation: Department of Medical Microbiology and Genitourinary Medicine, University of Liverpool, Liverpool, UK.|Department of Virology, Hannover Medical School, Hannover, Germany.|Departments of Applied Diagnostics and Computational Chemistry, GlaxoSmithKline, Medicines Research Centre, Stevenage, UK.
authors.forename: A
authors.initials: A
authors.lastname: Viejo-Borbolla
authors.affiliation: Departments of Applied Diagnostics and Computational Chemistry, GlaxoSmithKline, Medicines Research Centre, Stevenage, UK.
authors.forename: P
authors.initials: P
authors.lastname: Thomas
authors.affiliation: Departments of Applied Diagnostics and Computational Chemistry, GlaxoSmithKline, Medicines Research Centre, Stevenage, UK.
authors.forename: E D
authors.initials: ED
authors.lastname: Blair
authors.affiliation: Department of Virology, Hannover Medical School, Hannover, Germany.|Department of Medical Microbiology and Genitourinary Medicine, University of Liverpool, Liverpool, UK.
authors.forename: T F
authors.initials: TF
authors.lastname: Schulz
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D002460:Cell Line; D015686:Gene Products, env / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D005822:Genetic Vectors; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008561:Membrane Fusion / Q000502:physiology*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity*; D009154:Mutation; D041681:NIH 3T3 Cells; D011487:Protein Conformation
chemical_list: D015686:Gene Products, env