Immunoblots of TX-100-soluble and -insoluble fractions obtained at 4°C from OLGs infected with influenza virus or VSV. Monoclonal antibodies against HA (A) or VSVG (B) were used. Molecular weight markers were run alongside the extracts, as marked by horizontal bars. Samples are from the isolated viruses (v) or from cells (c), either infected (+) or noninfected (−). TX-100-soluble and -insoluble fractions are indicated by “s” and “i,” respectively. (A) HA. Lane 1 (v), solubilized influenza virus. The antibody marks HA at about 80 kDa (arrow) as well as a cluster of smaller proteins (accolade). Lane 2, TX-100-soluble fraction from uninfected OLGs; lane 3, TX-100-soluble fraction from influenza virus-infected OLGs; lane 4, TX-100-insoluble fraction from influenza virus-infected OLGs; and lane 5, TX-100-insoluble fraction from uninfected OLGs. Taking into account some nonspecific staining of the antibody (lanes 2 and 5), it is evident that HA (80-kDa band, arrow) primarily resides in the detergent-insoluble fraction (lane 3 versus lane 4). (B) VSVG. Lane 1 (v), solubilized VSV. The antibody demonstrates the presence of VSVG at about 60 kDa; lane 2, TX-100-soluble fraction from uninfected OLGs; lane 3, TX-100-soluble fraction from VSV-infected OLGs; lane 4, TX-100-insoluble fraction from VSV-infected OLG; and lane 5, TX-100-insoluble fraction from uninfected OLGs. Note that virtually all VSVG is present in the soluble fraction (lane 3).