Rabies virus binding to the nicotinic acetylcholine receptor α subunit demonstrated by virus overlay protein binding assay

A virus overlay protein binding assay was used to study binding of 125I-labelled rabies virus to the acetylcholine receptor (AChR) from Torpedo californica electric organ membranes. After gel electrophoresis of electric organ membranes and transfer of proteins to nitrocellulose, 125I-labelled α-bungarotoxin, a curaremimetic neurotoxin, bound to a 40 kDa band and 125I-labelled rabies virus bound to 51 kDa and 40 kDa bands. Binding of rabies virus to the 40 kDa band was inhibited by unlabelled α-bungarotoxin. In blots of affinity-purified AChR, labelled virus bound to the 40 kDa α subunit and was competed by α-bungarotoxin. Based on binding of rabies virus to the α subunit and the ability of α-bungarotoxin to compete for binding, rabies virus appears to bind to the neurotoxin-binding site of the nicotinic AChR α subunit.