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Two Methods of Heterokaryon Formation to Discover HCV Restriction Factors
Published on: July 16, 2012
The non-primate hepacivirus 5' untranslated region possesses internal ribosomal entry site activity
Hazel Stewart1, Cheryl Walter1, Dale Jones1
1School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
Abstract:
The 5' untranslated region (5'UTR) of the recently described non-primate hepacivirus (NPHV) contains a region with sequence homology to the internal ribosomal entry site (IRES) of hepatitis C virus (HCV) and GB virus B (GBV-B). Here, we demonstrated internal translation initiation by the NPHV 5'UTR in a bicistronic vector. An RNA stem-loop upstream of the NPHV IRES was structurally distinct from corresponding regions in HCV and GBV-B, and was not required for IRES function. Insertion of the NPHV stem-loop into the corresponding region of the HCV 5'UTR within the HCV subgenomic replicon significantly impaired RNA replication, indicating that long-range interactions between the 5'UTR and cis-acting downstream elements within the NPHV genome are not interchangeable with those of HCV. Despite similarities in IRES structure and function between hepaciviruses, replication elements in the NPHV 5'UTR appear functionally distinct from those of HCV.
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