Likewise, MG-based assays provided direct experimental confirmation that the IGR is a bona fide transcription termination signal (Pinschewer et al., 2005) , and that intracellular levels of NP do not determine the balance between virus RNA replication and transcription (Pinschewer, Perez, and de la Torre, 2003), a finding conceptually similar to that reported for the paramyxovirus RSV (Fearns et al., 1997) .