Table 2.

Transformation activity of the putative trimerization mutant^a

	Foci				Transformation Efficiency
	Exp 1	Exp 2	Exp 3	Exp 4	Ave ± Std
ΔGPb	27	8	56	131	1
pcDNA	0	0	0	0	0
ΔGP Y590F + pcDNA	0	0	0	-	0
ΔGP Tri-M + pcDNA	0	0	0	-	0
ΔGP SUΔ103–352 + pcDNA	0	0	0	-	0
ΔGP Tri-M FLAG + pcDNA	-	0	0	-	0
ΔGPY590F + ΔGP SUΔ103–352	2	3	0	-	0.15 ± 0.20
ΔGP Tri-M + ΔGP Y590Fb	6	8	0	1	0.31 ± 0.47
ΔGP Tri-M FLAG + ΔGP Y590F	-	3	1	-	0.19 ± 0.25

^aTransformation assays of different mutant JSRV Env plasmids in 208F cells are shown, as described in Materials and Methods. Positive and negative controls were wild-type JSRV Env (ΔGP) and empty vector (pcDNA) respectively. Co-transfections of different plasmids were performed, and the numbers of foci are shown.

“-“, transfection with these plasmid combinations was not performed.

^bThe difference in transforming activities between ΔGP and the control (pcDNA3) was significant (p < 0.05 respectively, Mann-Whitney U-test). Likewise the difference between transformation by the combination of ΔGP Tri-M + ΔGP Y590F compared to pcDNA3 was significant (p < 0.05, Mann-Whitney U-test).