Identification of a putative Gag binding site critical for feline immunodeficiency virus genomic RNA packaging

Binding of FIV unspliced gRNA, spliced env mRNA, and mutant gRNAs to FIV Pr50^Gag analyzed by filter-binding assay. The membrane-bound radioactivity of: (A) The WT AD26 gRNA and the spliced env mRNA, and (B) the WT AD26 gRNA and the selected U⁸⁵CUG⁸⁸ mutant RNAs. Note that mutations in U⁸⁵CUG⁸⁸ not only affected the RNA binding affinity, but also the binding plateau. Error bars represent the SD from the mean of three independent experiments.