BINDING OF A CELLULAR FACTOR TO THE 3'-UNTRANSLATED-REGION OF THE RNAGENOMES OF ENTEROVIRUS AND RHINOVIRUS PLAYS A ROLE IN VIRUS-REPLICATION

The presence of cellular factors that bind to the 3' untranslated regi on (UTR) of picornaviruses was investigated by electrophoretic mobilit y shift assays (EMSAs). A cellular factor(s) that binds specifically t he 3' UTR of polio-, coxsackie-and rhinoviruses was detected. Furtherm ore, this factor(s) is distinct from those which bind to the 5' termin al 88 nt (the 'cloverleaf') of poliovirus. Mutations within the 3' UTR which decrease the affinity of the RNA for the cellular factor in EMS As decrease RNA replication and virus viability. Revertants of these m utants display changes which are predicted to stabilize the RNA second ary structure of the 3' UTR. These results indicate that binding of a cellular factor to the UTR plays a role in virus replication and that RNA secondary structure is important for this function.