A promoter activity is present in the DNA sequence corresponding to the hepatitis C virus 5′ UTR
Nucleic Acids Research. 2003-02-15; 31(4): 1275-1281
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Dumas E(1), Staedel C, Colombat M, Reigadas S, Chabas S, Astier-Gin T, Cahour A, Litvak S, Ventura M.
(1)UMR 5097 CNRS, Université Victor Segalen Bordeaux 2, Institut Fédératif de Recherches 66 Pathologies Infectieuses, 146 rue Léo Saignat, 33076 Bordeaux
The hepatitis C virus (HCV) 5′ untranslated region (UTR) has been extensively studied with regard to its internal ribosomal entry site (IRES) activity. In this
work we present results suggesting the existence of a strong promoter activity carried by the DNA sequence corresponding to the HCV 5′ UTR. This activity was not detected when the HCV 5′ UTR sequence was replaced by HCV 3′ UTR or poliovirus 5′ UTR sequences. These results were further confirmed by using
bicistronic constructions. We demonstrated the presence of an mRNA initiated in this 5′ UTR sequence and located the initiation site by the 5′ RACE method at nucleotide 67. Furthermore, northern experiments and flow cytometry analysis showed the unambiguous activity of such a promoter sequence in stably transfected cells. Our results strongly suggest that the data obtained using bicistronic DNA constructs carrying the HCV 5′ UTR should be analyzed not only at the translational but also at the transcriptional level.