Development of a flexible and specific gene delivery system for production of murine tumor models

Abstract

To develop models of human cancer we have expressed the avian retroviral receptor, TVA, under a variety of mammalian promoters in transgenic mice, thus rendering mice susceptible to infection with avian leukosis virusderived gene vectors. TVA-based retroviral gene transfer oers advantages over current murine models of human cancer. A single transgenic mouse line can be used to evaluate multiple genetic lesions, individually and in combination. Furthermore, mutant genes are introduced somatically into animals, as occurs in the majority of naturally occurring tumors. Because the avian viral vectors replicate only in avian cells, the viral receptor in infected transgenic mouse cells remains available for multiple rounds of infection with dierent ASLV vectors. We discuss the theoretical and practical aspects of using recombinant avian retroviruses with TVA transgenic mice to generate cancer models.

Use of MMTV-Wnt-1 transgenic mice for studying the genetic basis of breast cancer

“…Recently, a novel method has been used to transduce oncogenes into somatic cells of a speci®c tissue (reviewed by Fisher et al, 1999) using sub-group A avian leukosis virus (ALV-A) as a vector. Transgenic expression of tv-a, encoding the receptor for ALV-A, from a cell type-speci®c promoter, permits tissuespeci®c infection with ALV-A, which does not produce infectious virus in mammalian hosts.…”

FGF-20 and DKK1 are transcriptional targets of β-catenin and FGF-20 is implicated in cancer and development

“…293 cells were engineered to produce Tva, the avian leukosis subgroup A virus receptor, allowing efficient infection by the avian retroviral vector RCAS (Fisher et al, 1999). In addition, the b-catenin/TCF reporter construct, pOT, was inserted in the genome of this cell line to monitor b-catenin/ TCF activity (Rubinfeld et al, 1993).…”

“…To generate 293Top cells, the kidney embryonic epithelial cell line 293 was first transfected with pcDNA6-tva (Fisher et al, 1999), a construct expressing the ALV receptor Tva, using stable calcium phosphate (Stratagene) according to the manufacturer's instructions. After selection with 5 mg/ml blastocidin, one clone was chosen for transfection with the b-catenin luciferase reporter pOT and a plasmid carrying a neomycin-resistant gene.…”

Complementation of melanocyte development in SOX10 mutant neural crest using lineage‐directed gene transfer

“…The vector pGWItv-a800 contains a GW cloning cassette for promoter sequence introduction, intronic sequence from pCI, and the gene tv-a800 that encodes for the smaller GPI-linked isoform of TVA (Fisher et al, 1999). To assess this construct, the same Pax3 promoter sequence was transferred into pGWItv-a800 destination vector construct by using GW recombination as described for P3PlacZ (Fig.…”

“…This system is based upon subcloning a gene of interest into an avian leukosis retroviral expression system, the RCAS vector (Hughes et al, 1987). Because RCAS virus cannot infect mammalian cells, the RCAS virus needs to be coupled with a transgenic mouse line expressing the viral receptor tv-a gene (TVA) from a tissue-specific promoter (for review, see Fisher et al, 1999). Transgenic mice and cells that are engineered to express the TVA receptor are permissive for infection by RCAS virus in actively dividing cells and genes cloned into the RCAS virus are expressed in infected cells from the long terminal repeat (LTR).…”