Similar interactions of the poliovirus and rhinovirus 3D polymerases with the 3 ' untranslated region of rhinovirus 14

We showed previously that a human rhinovirus 14 (HRV14) 3' untranslated reg ion (3' UTR) on a poliovirus genome was able to replicate with nearly wild- type kinetics (J. B. Rohll, D. H. Moon, D. J. Evans, and J. W. Almond, J, V irol 69:7835-7844, 1995). This enabled the HRV14 single 3' UTR stem-loop st ructure to be studied in combination with a sensitive reporter system, poli ovirus FLC/REP, in which the capsid coding region is replaced by an in-fram e chloramphemicol acetyltransferase (CAT) gene. Using such a construct, we identified a mutant (designated mut4), in which the structure and stability of the stem were predicted to be maintained, that replicated very poorly a s determined by its level of CAT activity. The effect of this mutant 3' UTR on replication has been further investigated by transferring it onto the f ull-length cDNAs of both poliovirus type 3 (PV3) and HRV14. Virus was recov ered with a parental plaque phenotype at a low frequency, indicating the ac quisition of compensating changes, which sequence analysis revealed were, i n both poliovirus- and rhinovirus-derived viruses, located in the active-si te cleft of 3D polymerase and involved the substitution of Asn18 for Tyr. T hese results provide further evidence of a specific interaction between the 3' UTR of picornaviruses and the viral polymerase and also indicate simila r interactions of the 3' UTR of rhinovirus with both poliovirus and rhinovi rus polymerases.