Viral Protein–Nucleic Acid Interaction: South (North)-Western Blot

Maize streak virus (MSV) genome has four open reading frames. C1 and C2 encoded by the complementary sense are required for virus replication, while V1 and V2 encoded by virion sense are required for infectivity. V1 encodes movement protein (MP), while V2 encodes coat protein (CP). Deletion or mutation of MSV CP does not prevent virus replication in single cells or protoplasts but leads to a loss of infectivity in the inoculated plant suggesting that MSV CP is required for virus movement. Towards understanding the role of MSV CP and MP in virus movement, the interaction of MSV CP and MP with viral DNA was investigated using the South-western assay. Wild type and truncated MSV CPs and MP were expressed in E. coli and the expressed CPs and MP were used to investigate interaction with single-stranded (ss) and double-stranded (ds) DNA. The results showed MSV MP does not bind DNA in the assay while MSV CP bound ss and ds viral and uidA DNA in a sequence non-specific manner