It has been observed that host-encoded proteins participate
in viral replication (1-4). The phosphorylated form of calreticulin
interacts with the 3' (+)-SL RV RNA, a cis-acting
element necessary for (-)-strand RNA synthesis (15). Further,
after RV infection, the RNA binding activity of this form
of calreticulin and its affinity for the 3' end of RV RNA
increases temporally with the appearance of (-)-strand RNA
synthesis (15). These observations suggest that the specific
binding of calreticulin to the RV 3' (+)-SL RNA is important
in regulating RV RNA synthesis.