Rev sequences used for computational prediction of tertiary structures. A. Schematic representations of the reference EIAV R1 Rev165 and R1 deletion mutants, Rev∆HVR and Rev135. The residue numbers indicate N and C termini and boundaries of deleted regions. The locations of functional motifs are indicated: NES: nuclear export signal, ARM: arginine-rich motif, HVR: hypervariable region. B. Alignment of Rev165 and RevFDD, derived from the fetal donkey dermal cell-adapted Chinese strain EIAVFDD-10 . Sequences shown to be non-essential for nuclear export activity (exon1 and HVR ) are underlined, while characterized functional motifs (NES, ARM-1, and ARM-2) are boxed.