Fig. 3

Characterization of“single virus”vectors

(A) Transcriptional activity of vectors possessing deletions in the 3′LTR (see Materials and Methods for precise boundaries of deletions). Luciferase activities were determined 48 hours after infection with the different vectors as indicated on the y axis. Enzymatic activities were normalized for the amount of total protein of the samples and the copy number of the luciferase gene in the different cell populations. The activity of the unmodified original SFG Luc vector was set arbitrarily as 100%. (B) Regulation of luciferase activity in NIH3T3 cells infected with“single virus”vectors. NIH3T3 cells were infected with different luciferase vectors as indicated in the“vector”column and split into replica plates. Luciferase activities of the off- (solid bar) and on state (shaded bar) were determined 48 hours after induction of gene expression. The relative transduction efficiency, normalized for pro viral copy number, is shown in the“relative transduction efficiency”column. The value of the original SFG Luc vector was arbitrarily set as 1. The relative induction of gene expression is given in the“relative induction”column. Induction of gene expression, normalization and calculation of the values was done as described in the legend to Figure 2.