FIG. 2.

Cellular actin in virions fractionates as a tegument protein. Purified extracellular Becker virions (lane V; 10 μg) were treated with either 1% NP-40 or 1% NP-40 plus 1 M NaCl, from which soluble (S) and pellet (P) fractions were isolated by high-speed centrifugation. Proteins were separated by SDS-PAGE and Sypro staining was used to visualize total protein. Protein bands associated with the capsid structure (open arrowheads) pellet with or without 1 M NaCl and include the MCP. The migration positions of molecular mass markers are shown on the left in kilodaltons.