TABLE 3.

Effect of accessory gene expression on transduction efficiency^a

Gene of interest	Expression plasmid (amt transfected [μg])	Gene expression	Mean titerb (LFU/ml of virus stock) ± SD
			Dividing cells	Growtharrested cellsc
vif	pGP-RRE3 (7)	−	(8.8 ± 0.6) × 105	ND
	pGP-RRE1 (7)	+	(8.8 ± 0.7) × 105	(9.2 ± 1.7) × 105
vpr	None	−	(3.1 ± 1.0) × 105	(5.1 ± 1.3) × 105
	pCI-vpr (1)	+	(3.0 ± 0.2) × 105	(3.5 ± 0.5) × 105
	pCI-vpr (3)	+	(3.2 ± 0.9) × 105	(3.6 ± 1.1) × 105
vpu	None	−	(4.0 ± 0.8) × 105	(3.2 ± 0.5) × 105
	pCI-vpu (1)	+	(3.7 ± 1.1) × 105	(3.3 ± 1.2) × 105
	pCI-vpu (3)	+	(3.5 ± 0.1) × 105	(3.0 ± 0.0) × 105
nef	None	−	(4.0 ± 0.8) × 105	(3.2 ± 0.5) × 105
	pCMV-nef (1)	+	(1.5 ± 0.5) × 105	(2.0 ± 0.5) × 105
	pCMV-nef (3)	+	(1.0 ± 0.0) × 105	(1.0 ± 0.1) × 105
	MLV vectord		(5.5 ± 0.2) × 106	4.0 ± 3.0

^aFor vif, 7 μg of the gag-pol expression plasmid (either pGP-RRE3 or pGP-RRE1), 8 μg of pH4Z, and 5 μg of pRV67 were transfected. For the rest, 6 μg of pGP-RRE3, 7 μg of pH4Z, 4 μg of pRV67, and the indicated amount of the expression plasmid were transfected. The total amount of DNA used for transfection was kept at 20 μg by adding pCI-neo. Results are from a representative experiment of a total of at least three performed. 

^bTiter was measured on 293T cells by counting the number of blue colonies following X-Gal staining 48 h after transduction. 

^cThe cells were treated with aphidicolin (15 μg/ml) for 24 h prior to transduction, and the medium was changed with fresh aphidicolin every 24 h. ND, not done. 

^dMLV vectors were generated by cotransfection of pHIT111 (5 μg), pHIT60 (5 μg), and pRV67 (5 μg).