UL6 and UL25 are present in B capsids from wild-type- and hr64-infected cells. The presence or absence of UL6 and UL25 in KOS- and hr64-infected Vero cell extracts, in B capsids from KOS- and hr64-infected cells, and in virions from KOS-infected Vero cells was determined as described under Materials and Methods. Proteins were revealed by Western blotting with α-UL6 antibodies and alkaline phosphatase-conjugated secondary antibodies (A) or by ECL Western blotting with a UL25 polyclonal antibody and horseradish peroxidase-labeled secondary antibodies (B). Panel A lanes: 1, B capsids from KOS-infected Vero cells; 2, B capsids from hr64-infected Vero cells; 3, mock-infected Vero cell extracts; 4, KOS-infected Vero cell extracts; 5, hr74-infected Vero cell extracts; 6, virions from KOS-infected Vero cells (this lane was developed for a longer time to visualize the band). Panel B lanes: 1, mock-infected Vero cell extracts; 2, KOS-infected Vero cell extracts; 3, B capsids from KOS-infected Vero cells; 4, B capsids from hr64-infected Vero cells; 5, extracts from Vero cells infected with virus lacking UL25; 6, virions from KOS-infected Vero cells.