The RNA binding region of the paramyxovirus SV5 V and P proteins

The V/P gene of simian virus 5 (SV5) encodes two proteins, V (222 residues) and the phosphoprotein P (392 residues). The V and P proteins are amino coterminal for 164 residues, but they have unique carboxy termini due to addition of two nontemplated G residues to the P mRNA during transcription. We have shown that the V and P proteins bind RNA by using both Northwestern blot analysis and ultraviolet-light crosslinking. The RNA-binding region has been mapped to a region in the P and V proteins which contains five basic residues (K74, K76, K77, R79, K81). Either deletion of the basic residues or substitution of the basic residues with alanine inhibited RNA binding by the V or P proteins.