Low efficiency of the 5' nontranslated region of hepatitis A virus RNA in directing cap-independent translation in permissive monkey kidney cells.

To characterize in vivo the translational control elements present in the 5' nontranslated region (5' NTR) of hepatitis A virus (HAV) RNA we created an HAV-permissive monkey kidney cell line (BT7-H) that stably expresses T7 RNA polymerase and carries out cytoplasmic transcription of uncapped RNA from transfected DNA containing the T7 promoter. The presence of an internal ribosomal entry site (IRES) within the 5' NTR of HAV was confirmed by using BT7-H cells transcribing bicistronic RNAs in which the 5' NTR was placed within the intercistronic space, controlling translation of a downstream reporter protein (bacterial chloramphenicol acetyltransferase)