XMRV viral proteins. (A) XMRV viral proteins identified by WB analysis using goat polyclonal antibodies to Friend MuLV (anti-MuLV) at a 1:2000 dilution and to Env (gp69/71) of Rauscher-MuLV (anti-Env) at a 1:1000 dilution. Env, Envelope protein; TM, Transmembrane protein; MA, Matrix protein; CA, Capsid protein; and NC, Nucleocapsid protein. The gag precursor (p68/p80) and proteolysis intermediate (p12-CA) are italicized. (B) Competitive inhibition of anti-MuLV (Strips 2-6) and anti-Env (Strip 8) binding to native XMRV proteins on WB strips with recombinant XMRV proteins. Inhibitors of recombinant proteins and concentrations for specific strips are listed in the inserted table.