Single stranded RNA viruses contain both messenger RNA for protein synthesis and an RNA template for replication. Utilizing an experimental system which permits the study of each of these functions separately both in vivo and in vitro, the proposed research aims at characterizing the functional domains of the QB replicase. Such domains involve the catalytic site, RNA recognition and binding, and interaction sites for a variety of host proteins. Studies planned involve manipulation of viral RNA sequences. A second objective is the study of the viral nucleotide sequences coding for the production of the QB replicase. Chemical, biochemical and molecular biological approaches will combine to correlate the function of the viral genome with its primary and secondary structure. %%% The genome of single stranded RNA viruses is extrordinarily susceptible to mutation. One consequence of this is a pronounced difficulty in developing host resistance to viral attack. Since the viral RNA codes both for its replication and for synthesis of critical proteins, it has been difficult to study these two activities in isolation. The proposed research into the details of the behavior of the viral genome is based on work in the investigator's laboratory which resulted in the development of an experimental system permitting study of these two aspects of viral genome function independently. A variety of molecular biological and biochemical approaches will be employed to relate the structure of the viral genome with its ability to reproduce and infect cells.
