A recombinant classical swine fever virus with a marker insertion in the internal ribosome entry site.

摘要: Based on an infectious cDNA clone of classical swine fever virus (CSFV) strain Alfort/187 (Ruggli et al., J Virol 70, 3478–3487, 1996) a full-length was constructed harbouring nonviral 44 base insertion in the internal ribosome entry site (IRES) within 5′ nontranslated region (5′NTR) genome. Genome size RNA transcribed vitro served as positive control routine RT–PCR used to detect CSFV diagnostic material. Unexpectedly this proved be upon transfection into susceptible cells. The replication kinetics resulting vA187-Ins44 were characterized and found indistinguishable from its parent virus. However, deletion mutant with 29 inserted bases missing detected after multiple cell culture passages. secondary structure analysis 5′NTR showed that destroyed stem-loop pseudoknot previously described essential for replication, demonstrating insertions functionally IRES element are tolerated by CSFV.