title: A murine leukemia virus with Cre-LoxP excisible coding sequences allowing superinfection, transgene delivery, and generation of host genomic deletions.
abstract: BACKGROUND
  To generate a replication-competent retrovirus that could be conditionally inactivated, we flanked the viral genes of the Akv murine leukemia virus with LoxP sites. This provirus can delete its envelope gene by LoxP/Cre mediated recombination and thereby allow superinfection of Cre recombinase expressing cells.
  
  
  RESULTS
  In our studies, the virus repeatedly infected the cell and delivered multiple copies of the viral genome to the host genome; the superinfected cells expressed a viral transgene on average twenty times more than non-superinfected cells. The insertion of multiple LoxP sites into the cellular genome also led to genomic deletions, as demonstrated by comparative genome hybridization.
  
  
  CONCLUSIONS
  We envision that this technology may be particularly valuable for delivering transgenes and/or causing deletions.
authors.affiliation: Department of Microbiology and Immunology, University of California, San Francisco 94143-0414, USA. cliffw@itsa.ucsf.edu
authors.forename: Clifford L
authors.initials: CL
authors.lastname: Wang
authors.forename: J Graeme
authors.initials: JG
authors.lastname: Hodgson
authors.forename: Tiffany
authors.initials: T
authors.lastname: Malek
authors.forename: Finn Skou
authors.initials: FS
authors.lastname: Pedersen
authors.forename: Matthias
authors.initials: M
authors.lastname: Wabl
mesh_terms: D016475:3T3 Cells; D000818:Animals; D017353:Gene Deletion; D015752:Genes, env; D005822:Genetic Vectors; D016679:Genome, Viral; D019426:Integrases / Q000235:genetics*; D009052:Leukemia Virus, Murine / Q000235:genetics*; D051379:Mice; D017384:Sequence Deletion; D015163:Superinfection / Q000821:virology; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D014764:Viral Proteins; C045073:Cre recombinase; D019426:Integrases