In vivo labelling of viral proteins with ⁷⁵selenomethionine

A method is described for in vivo labelling of viral proteins with a gamma ray emitting radionuclide. The amino acid methionine labelled with 75Se instead of 35S will be accepted by cells in culture for protein synthesis. A high specific labelling of viral proteins is achieved which allows rapid detection of virus or viral proteins in gradient centrifugation and PAGE as well as further biochemical or serological analysis of the proteins. As an example hog cholera virus (family Togaviridae) was labelled with [75Se]methionine and analyzed in sucrose and CsCl gradients and in PAGE. The results were similar to those obtained by labelling of proteins with [35S]methionine.