FIG. 5.

Amino acid alignment of envelope-SU of FeLV. The predicted amino acid sequences of the mature SU of FeLV-A-61E (35), FeLV-B-90Z (5), FeLV-B-GA (63), and the endogenous FeLV clone CFE-6 (22) are shown. Included is an FeLV-B E5.14 clone that was obtained from MDTF-FePit2 cells infected with supernatant from feline fibroblasts that had been transfected with FeLV-A-61E. FeLV-A-61E is shown as the reference sequence, and for the other SU proteins only amino acids that differ are given. Amino acid residues are shown in single-letter code, and conserved residues are indicated with a dot. A gray box surrounds the VRA, the VRB, and the PRR. Residues of the representative cloned virus FeLV-B-E5.14 (GenBank accession no. AF403716) are double underlined at positions that are divergent between this clone and FeLV-B-GA.