ERVW-1 and infection: To determine whether WNVNY99 NS4B localizes to the IMS, characterized in Fig. 1 and defined by components of the flavivirus replication complexes including the replicating double-stranded RNA (dsRNA) [4], [19], NS1 protein [16], [17], and envelope protein [19], we conducted a co-localization assay on fixed cells by confocal IFM at 24 hr after infection (Fig. 3).