Retroviral vectors SNV-MPL, N2, and gene transfer efficiency.

Upper panels depict diagrams of the MoMLV-derived vectors used in these studies. The relevant restriction enzymes and the distance between them are indicated. Ψ⁺ represents the packaging signal. Lower panels illustrate the gene transfer efficiency obtained with each vector as assayed by Southern blotting. (A) pSNV-MPL contains the MPL cassette under the transcriptional control of the spleen necrosis virus U3 promoter (SNV) and the neo marker gene. Southern blotting was performed on genomic DNA extracted from SNV-MPL producer cells, SNV-MPL-infected 3T3 cells, SNV-MPL- infected WEHI 231 B-cell line, SNV-MPL cocultivated primary, spleen B cells, and copy number controls as indicated above each lane. (B) pN2 (provided by E. Gilboa) contains only the neo marker gene driven directly by MoMLV LTR. Southern blotting analysis was performed on genomic DNA extracted from N2 producer cells, N2-infected HB97 B-cell line, N2 cocultivated primary, spleen B cells, and copy number controls as indicated above each lane.