I wonder if recombinant transmembrane proteins need to be modified, for instance fusing a gag protein recognized sequence to the intracellular region, such that the TM proteins can be recognized and display on the surface of the gag VLP? I found the unmodified TM proteins and gag protein are co-expression to produce the VLP display transmembrane proteins. In this case, will the VLP randomly bring any TM proteins accompany with the host membrane during budding?