REPLICATION-COMPETENT PICORNAVIRUSES WITH COMPLETE GENOMIC RNA 3'-NONCODING REGION DELETIONS

The genomic RNA 3' noncoding region is believed to be a major cis-acti ng molecular genetic determinant for regulating picornavirus negative- strand RNA synthesis by promoting replication complex recognition. We report the replication of two picornavirus RNAs harboring complete del etions of the genomic RNA 3' noncoding regions. Our results suggest th at while specific 3'-terminal RNA sequences and/or secondary structure s may have evolved to promote or regulate negative-strand RNA synthesi s, the basic mechanism of replication initiation is not strictly templ ate specific and may rely primarily upon the proximity of newly transl ated viral replication proteins to the 3' terminus of template RNAs wi thin tight membranous replication complexes.