Stable recombinants of bovine viral diarrhea virus containing a hepatitis C virus insert.

Here we report on a segment in the genomic 3' non-translated region (3'NTR) of bovine viral diarrhea virus (BVDV) that is accessible for the insertion of foreign sequence elements such as the 5'NTR of hepatitis C virus. Recombinant viruses exhibited replication kinetics similar to those of the parental strain, and characterization of RNA species after several passages revealed that foreign inserts had the same genetic stability as the BVDV 3'NTR. The generation of such BVDV recombinants is relevant for several applications.

Nuclear factors are involved in hepatitis C virus RNA replication.

Unraveling the molecular basis of the life cycle of hepatitis C virus (HCV), a prevalent agent of human liver disease, entails the identification of cell-encoded factors that participate in the replication of the viral RNA genome. This study provides evidence that the so-called NF/NFAR proteins, namely, NF90/NFAR-1, NF110/NFAR-2, NF45, and RNA helicase A (RHA), which mostly belong to the dsRBM protein family, are involved in the HCV RNA replication process. NF/NFAR proteins were shown to specifically bind to replication signals in the HCV genomic 5' and 3' termini and to promote the formation of a looplike structure of the viral RNA. In cells containing replicating HCV RNA, the generally nuclear NF/NFAR proteins accumulate in the cytoplasmic viral replication complexes, and the prototype NFAR protein, NF90/NFAR-1, stably interacts with a viral protein. HCV replication was inhibited in cells where RNAi depleted RHA from the cytoplasm. Likewise, HCV replication was hindered in cells that contained another NF/NFAR protein recruiting virus. The recruitment of NF/NFAR proteins by HCV is assumed to serve two major purposes: to support 5'-3' interactions of the viral RNA for the coordination of viral protein and RNA synthesis and to weaken host-defense mechanisms.