Mutant del20NLS-NP maintains nucleic acid binding as WT-NP. A. 293 T cells were transfected with plasmids to express WT-NP, del20NLS-NP, or vector control as indicated. Total protein extracts were isolated and subject to immuno purification with anti-FLAG antibody and elution with FLAG peptide. Elutant was separated via SDS-PAGE gel and stained with Coomassie blue. B. Purified NP proteins incubated with biotin labeled single stranded DNA were resolved via native PAGE gel, transferred to nitrocellulose membrane, and probed with Streptavidin-HRP. Purified del20NLS-NP and WT-NP shift the biotin labeled ssDNA as Streptavidin-HRP is detected with ECL reagents. Unbound biotin labeled ssDNA was not detected. Shown is a representative experiment, repeated in triplicate.