“…Moreover, the novel approach can be used to study individual steps of viral replication in the absence of cell-membrane barriers. Several interesting observations regarding protein-protein interactions, the role of membranes, of cellular membranous components or soluble cellular factors, or of inhibitors of viral RNA synthesis, have been published (Barton and Flanegan, 1993;Molla et al, 1993cMolla et al, , 1994Barton et al, 1995;Parsley et al, 1997;Cuconati et al, 1998;Towner et al, 1998). The use of the cell-free cellular extract for studies of poliovirus RNA replication, however, is still in the early stages of exploitation.…”