IDENTIFICATION AND CHARACTERIZATION OF HOST FACTOR INTERACTIONS WITH CIS-ACTING ELEMENTS OF RUBELLA-VIRUS RNA

We have analyzed the function of cis-acting elements of rubella virus RNA and the components which interact with these elements in viral RNA replication. We demonstrated that the 5'- and 3'-terminal sequences f rom RV RNA promote translation and negative-strand RNA synthesis of ch imeric chloroamphenicol acetyltransferase (CAT) RNAs. These sequences have a potential to form stem-loop (SL) structures and bind cellular p roteins specifically in RNA gel-shift and UV cross-linking assays. The 5' end binding proteins were identified to be Ro/SSA-associated antig ens by virtue of being recognized in an RNA complex by an autoimmune p atient serum with Ro antigen type specificity. Purification and sequen ce analysis of the 3' end binding protein revealed that it is a homolo gue of human calreticulin. The role of host proteins in RV replication is discussed.