Fig. 1.

Infectivity studies of GALV and KoRV retroviral vectors. (A) Titers of GALV and KoRV enveloped vectors containing different gagpol proteins. MDTFPiT1 cells were exposed to GALV or KoRV enveloped vectors assembled with either GALV or KoRV gagpol proteins. Titers were normalized to GALV env with GALV gagpol vectors (titer, average ± SEM, 2.6 × 10⁶ ± 9.3 × 10⁵) and were determined by averaging the number of blue-forming units (bfu) per milliliter of vector supernatant from at least three independent experiments ± SEM. (B) Alignment of part of GALV gagpol and KoRV gagpol with two L domains shown in boxes. The two amino acids as encoded by KoRV gagpol and targeted for mutagenesis in GALV gagpol are highlighted in yellow. Residue numbers for GALV gagpol. (C) MDTFPiT1 cells were exposed to GALV or KoRV enveloped vectors assembled with mutant GALV/SRLPIY gagpol proteins. Titers were normalized as described in A.