Retrovirus-mediated gene transfer into embryonal carcinoma and hemopoietic stem cells: expression from a hybrid long terminal repeat

Generation of a high titre retroviral vector for endothelial cell-specific gene expression in vivo

“…12,[15][16][17] We sought to explore the possibility of modulating the viral promoter activity using proximal regulatory sequences of the ppET1 promoter, in retroviral vectors in which only the viral enhancer was replaced. The −177 to +33 and the −177 to −37 promoter sequences of the ppET1 gene were used to replace the viral enhancer between the NheI and XbaI sites, to generate hybrids E and F, respectively ( Figure 2).…”

“…10,11 Similarly, replacement of the MLV enhancer with that of a polyoma mutant selected to grow in embryonal carcinoma cells overcame the MLV LTR restriction in these cells. 12 Insertion of the muscle creatine kinase enhancer between the viral enhancer and promoter resulted in differentiation-specific expression in myogenic cells. 13 However, appropriate cell specificity was not obtained in this latter case nor following addition of lymphoid-specific enhancers.…”

Expression pattern of CD2 locus control region containing retroviral vectors in hemopoietic cells in vitro and in vivo

“…5 When the fragment encompassing this mutant enhancer was used to replace the Moloney murine leukemia virus (MoMLV) enhancer in a recombinant retroviral construct, expression was obtained in EC cells and in the mouse hemopoietic system. 8,9 The discovery of locus control region (LCR) sequences has raised the expectation that well controlled expression levels of retrovirally introduced sequences will become feasible. LCR sequences are defined as regulatory units that confer a cell type-specific, copy number-dependent and integration site-independent expression pattern on a linked gene in transgenic animals.…”

In vivo methotrexate selection of murine hemopoietic cells transduced with a retroviral vector for Gaucher disease

“…Both IG-GC2 and IG-GC12 contain a hybrid Moloney murine leukemia virus LTR since the wild-type enhancer in U3 was replaced by a mutant polyoma enhancer, ⌬Mo+PyF101. [17][18][19] Generation of both the PA2 (IG-GC2) and PA125 (IG-GC12) amphotropic retrovirus producer cell lines have been described. 10,17 The PA2 retroviral producer cell line was tested for the absence of RCR using a S + /L − foci assay after amplification on mus dunni cells.…”