Polypyrimidine tract-binding protein (PTB) inhibits Hepatitis C virus internal ribosome entry site (HCV IRES)-mediated translation, but does not affect HCV replication

• Published in: Archives of virology Vol. 149; no. 10; pp. 1955 - 1970
• Main Authors: TISCHENDORF, J. J. W, BEGER, C, KORF, M, MANNS, M. P, KRÜGER, M
• Format: Journal Article
• Language: English
• Published: Wien Springer 01.10.2004; New York, NY Springer Nature B.V
• Subjects: 5' Untranslated Regions; Biological and medical sciences; Biopsy; Cell Line, Tumor; Fundamental and applied biological sciences. Psychology; Genes, Reporter; Hepacivirus - growth & development; Hepatitis C; Hepatitis C virus; Human viral diseases; Humans; Infections; Infectious diseases; Liver - chemistry; Liver - pathology; Liver cirrhosis; Luciferases - analysis; Luciferases - genetics; Medical sciences; Microbiology; Miscellaneous; Plasmids; Polypyrimidine Tract-Binding Protein - genetics; Polypyrimidine Tract-Binding Protein - metabolism; Polypyrimidine Tract-Binding Protein - physiology; Protein Biosynthesis; Proteins; Ribonucleic acid; RNA; RNA, Antisense; RNA, Messenger - analysis; RNA, Viral - analysis; Up-Regulation; Viral diseases; Viral hepatitis; Virology; Virus Replication; Germany; Ribosome; Hepatic disease; Genetic translation; Infection; Virus; Binding protein; Viral disease; Digestive diseases; Replication; Flaviviridae; Hepatitis C virus; Hepacivirus; Viral hepatitis C
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s00705-004-0341-8

Polypyrimidine tract-binding protein (PTB) has previously been shown to affect Hepatitis C virus (HCV) IRES-mediated translation. In the present study we investigated the functional role of PTB for HCV translation, replication and chronic HCV infection. Bicistronic HCV IRES reporter plasmids and two different subgenomic replicons (bicistronic: pHCVrep1bBB7 (s1179I); monocistronic: pFK1-389/hyg-ubi/NS3-3'/5.1) were used to analyze the effects of PTB. Following transfection of plasmids expressing PTB RNA in sense or antisense orientation, translational activity and HCV RNA were analyzed by luciferase assay, quantitative real-time RT-PCR and northern blot analysis. Additionally, in liver tissue (n = 53) intrahepatic PTB RNA levels were determined by quantitative real-time RT-PCR. Significant inhibition of HCV IRES activity up to 42.6% was observed upon PTB sense RNA expression for HCV IRES reporter plasmids, while translational activity was enhanced up to 63.8% for PTB antisense RNA expression. In the HCV replicons PTB did not affect replication and no correlation was found between intrahepatic PTB mRNA levels and serum HCV RNA or histological changes in liver tissue of HCV infected patients. Although PTB inhibits HCV IRES-mediated translation from bicistronic reporter constructs, data obtained from two subgenomic HCV replicons and liver tissue do not indicate a significant role of PTB for HCV replication and chronic HCV infection.